F-Gas English Low GWP

1 Ľahká

What is the base unit of mass according to the International System of Units (Système International d’Unités)?

t

Pound

N

kg

2 Stredne ťažká

What process takes place in the condenser of a refrigeration system?

								The medium flowing through the evaporator (glycol, water) condenses, whilst the refrigerant evaporates.
							

								In the condenser, the refrigerant releases the heat absorbed in the evaporator into the surroundings.
							

								Hot refrigerant vapour is pumped from the compressor to the condenser, where it is cooled and then condensed. In this heat exchanger, the resulting liquid refrigerant is also slightly subcooled.   
							

The refrigerant releases the heat absorbed in the compressor via the condenser

3 Stredne ťažká

What determines the condensation temperature of an air-cooled unit?

On the ambient temperature.

On the evaporation (boiling) temperature.

On the compressor and discharge temperatures

On the superheat temperature.

4 Stredne ťažká

Is energy required when heat is transferred from the condenser to the surroundings?

								No, because according to the second law of thermodynamics, thermal energy always flows from a body at a higher temperature to a body at a lower temperature.
							

Yes, in every case.

The heat flow balances the energy input.

Yes, but only when using HFC refrigerants.

5 Stredne ťažká

What should you pay attention to during the operation of the condenser?

Pay attention to the fan’s operation and the ambient temperature.

								Care should be taken to ensure that the air temperature at the condenser inlet is lower than the air temperature at the condenser outlet.
							

								You should ensure the general maintenance of the condenser and keep the heat exchange surfaces clean.
							

								Ensure that the air temperature at the condenser outlet is higher than the condensation temperature.
							

6 Stredne ťažká

What criteria should be considered when selecting a suitable condenser?

								Condensers should be selected based on your own experience, and the condenser’s geometric parameters should be taken into account.
							

								These include size and the number of fans. The geometric parameters of the condenser must be taken into account.
							

								First and foremost, you should consider the operating noise level of the fans, the diameter of the connection pipes and the colour scheme.
							

								The required capacity of the condenser and the technical specifications declared by the manufacturer must be taken into account.
							

7 Stredne ťažká

How do contaminants (dust, particulates, deposits) affect the performance and efficiency of heat exchange surfaces in condensers?

								Contaminants do not significantly affect the efficiency and effectiveness of the heat exchange surfaces in condensers.
							

								Contaminants increase the heat transfer area and reduce the condensing pressure.
							

								Contaminants restrict heat transfer (reducing the heat transfer coefficient) and cause an increase in condensing temperature and pressure, which in turn leads to a reduction in the condenser’s efficiency.
							

								Contaminants restrict heat transfer (reducing the heat transfer coefficient) and cause a reduction in condensing pressure.
							

8 Stredne ťažká

If an air-cooled condenser becomes contaminated, will the condensation efficiency?

It will increase.

It will decrease.

It remains unchanged.

It will increase as a result of the fan speed being raised further.

9 Stredne ťažká

What can cause frost to form on the evaporator?

								Frost build-up on the evaporator increases airflow resistance and, consequently, causes the fan motor to work harder.
							

A reduction in the temperature of the cooled substance.

								An increase in refrigerant flow resistance and a reduction in the refrigerant flow rate through the evaporator.
							

a drop in cooling capacity.

10 Stredne ťažká

What happens when the evaporation temperature drops?

The compressor’s cooling capacity decreases.

The discharge temperature decreases.

The compressor’s cooling capacity increases.

The condenser fan speed increases.

11 Stredne ťažká

When is defrosting using the refrigerant possible?

								In the case of air-cooled chillers, only when the air temperature is above 0°C.  
							

Defrosting using the refrigerant is not possible at all.

								Never. We use electricity for defrosting (for example, using a special electric heater).  
							

Only when using speed-controlled fans.

12 Stredne ťažká

When can frost form on the evaporator surface?

Only in the case of air coolers, when the air temperature drops below 0°C.

Frost forms only when the refrigeration system is operating continuously.

In the case of finned evaporators.

Frost always forms on air coolers.

13 Stredne ťažká

In the case of extensive pipework systems, secondary evaporation of the refrigerant can be prevented by...

by insulating the pipes between the compressor and the condenser.

using larger-diameter pipes.

using smaller-diameter pipes.

additional cooling.

14 Stredne ťažká

How does hot gas defrosting of the evaporator work?

We switch on the gas heater directed at the evaporator.

This involves reversing the direction of rotation of the compressor.

We swap the outlet and inlet sides of the evaporator.

								Heated vapour (hot gas) from the compressor is directed into the evaporator piping.
							

15 Stredne ťažká

What is the function of the evaporator in a refrigeration system?

It evaporates the water flowing through the evaporator.

								Thanks to the evaporator, the cooled medium transfers heat to the boiling refrigerant.
							

It cools the refrigerant.

								It ensures that the refrigerant is superheated over the largest possible heat exchange surface area.
							

16 Stredne ťažká

What conditions must be met for the evaporator to be defrosted using electric heaters?

								Thanks to the forced air flow created by the fans, the heat from the heaters is transferred to the heat exchanger.  
							

								The electric heaters must be in contact with the evaporator’s heat exchange surface (the heater must touch the fins).
							

								The electric heaters must be positioned in direct contact with the refrigerant so that the refrigerant flowing through the evaporator is at a sufficiently high temperature.
							

								The electric heaters must be positioned beneath the evaporator’s heat exchange surface.
							

17 Stredne ťažká

Refrigerant distributor:

								acts as a buffer for the refrigerant in the event that the pressure upstream of the expansion valve is exceeded.
							

								ensures the even distribution of the refrigerant discharged by compressors connected in parallel.
							

								ensures even distribution of the refrigerant to the individual sections of the condenser.
							

								ensures an even distribution of the refrigerant to the individual sections of the evaporator.
							

18 Stredne ťažká

What are the possible methods of defrosting air coolers?

Electric defrosting only.

								Electric defrosting, liquid defrosting or defrosting using hot refrigerant vapour.
							

Hot gas defrosting.

Natural defrosting; there are no other effective methods.

19 Stredne ťažká

The boiling point increases (and consequently the rate of evaporation increases) if the pressure above the liquid...

Rises.

It behaves differently depending on the ambient temperature.

Falls.

Remains constant.

20 Stredne ťažká

MOP in thermostatic expansion valves stands for:

minimum flow opening.

								self-cleaning of the valve in the event of moisture in the refrigerant freezing.
							

maximum operating pressure.

maximum pressure switch protection.

21 Stredne ťažká

The function of a thermostatic expansion valve (TEV) in a refrigeration system is:

								to control the amount of refrigerant supplied to the evaporator depending on the superheat of the vapour leaving that heat exchanger.
							

								to consistently adjust the evaporation pressure in the condenser depending on the temperature of the refrigerant vapour leaving the condenser. 
							

								regulating the superheat of the refrigerant leaving the evaporator so that it is at the minimum value.
							

to maintain a constant suction pressure to the compressor.

22 Stredne ťažká

When using a capillary tube, what type of motor can be used in the compressor?

A low-speed motor should be used.

								An electronically commutated motor approved for use with the compressor should be used.
							

A motor with low starting torque can be used.

A motor with high starting torque must be used.

23 Stredne ťažká

What does the thermostatic expansion valve regulate?

Cooling.

The mass flow of the refrigerant injected into the evaporator.

Discharge temperature.

Evaporation pressure after.

24 Stredne ťažká

The refrigerant absorbs heat when...

it evaporates.

sublimates

it condenses.

freezes.

25 Stredne ťažká

In the case of a thermostatic expansion valve, the manufacturer specifies...

...the degree to which the valve is filled with refrigerant liquid.

...the superheat value during valve operation.

...the static superheat of the valve.

…the degree of refrigerant expansion.

26 Stredne ťažká

How do we charge a new or repaired system with refrigerant when it is fitted with an expansion valve

behind the condenser to the liquid refrigerant receiver.

to the suction side of the compressor.

								Charging with refrigerant takes place during operation via the outlet connection of the refrigerant capillary tube. 
							

in any way.

27 Stredne ťažká

What does a thermostatic/electronic expansion valve regulate?

Condenser subcooling by adjusting the condensing pressure.

The number of revolutions of the compressor per unit of time.

The amount of refrigerant by controlling the evaporator superheat.

The evaporation pressure, closing when it falls below the setpoint temperature.

28 Stredne ťažká

What does the MOP function in expansion valves mean?

This means that these expansion valves are set to limit subcooling.

This means that these expansion valves are set to a specific suction pressure.

								It means that these expansion valves are set to limit the maximum operating pressure.
							

This means that these expansion valves are set to prevent overheating.

29 Stredne ťažká

The lower the temperature of the liquid refrigerant upstream of the expansion valve,

								...the lower the theoretical coefficient of cooling efficiency qo will be, and the lower the system’s energy efficiency will be.
							

								 ...the lower the theoretical coefficient of refrigeration efficiency qo will be, and the lower the refrigeration capacity Qo will be.
							

								... the higher the theoretical coefficient of cooling capacity qo will be, and the greater the cooling capacity Qo will be.  
							

								  ...the lower the theoretical coefficient of cooling efficiency qo will be, whilst the cooling capacity Qo remains unchanged.  
							

30 Stredne ťažká

The MOP point in the expansion valve, due to the maximum evaporation temperature of the refrigeration system, ...

The value of the MOP point is irrelevant.

...must be approximately 7 K higher.

...must be approximately 7 K lower.

...must be approximately 5 K lower.

31 Stredne ťažká

What is the function of the suction pressure regulator?

								It limits the suction pressure and protects the compressor from excessively high suction pressure.
							

It maintains the suction pressure at a constant level.

To maintain the suction pressure at the highest possible level.

								It prevents a drop in suction pressure and, if necessary, shuts down the refrigeration system.
							

32 Stredne ťažká

What is the function of the valve regulating water flow through the condenser?

To maintain the condensing pressure at the lowest possible level.

To maintain the condensing pressure at the highest possible level.

To maintain the water temperature at the highest level.

To maintain the condensing pressure at a constant level.

33 Stredne ťažká

The use of a refrigerant distributor requires a thermostatic expansion valve …

… with internal pressure equalisation.

… with a MOP function.

… with an adsorption-type sensor filling.

… with external pressure equalisation.

34 Stredne ťažká

What properties should good insulation materials have?

It must be able to absorb large amounts of moisture.

It must have a low thermal conductivity.

It must have a good antistatic coating

It must have a high thermal conductivity.

35 Stredne ťažká

When do we encounter the superheated state?

								It is the temperature difference between the evaporation temperature and the ambient temperature.
							

It is a condition in which the compressor motor temperature rises excessively.

								This is the temperature difference between the actual vapour temperature and the vapour temperature at saturation.
							

								This is a state that arises as a result of the temperature difference between the suction side and the discharge side of a compressor.
							

36 Stredne ťažká

How can you check whether the liquid refrigerant is reaching the expansion valve without vapour bubbles?

We check this using a sight glass.

We check using a pressure gauge fitted on the discharge side of the compressor.

We are unable to check this.

We check using a liquid pressure gauge.

37 Stredne ťažká

The liquid lines are located...

between the evaporator and the compressor.

between the evaporator and the regenerative heat exchanger.

between the condenser and the liquid receiver.

between the compressor and the condenser.

38 Stredne ťažká

What is the function of the liquid receiver in a refrigeration system?

								The reservoir is used to further cool the liquefied refrigerant leaving the condenser.
							

								The tank is used to collect the liquid refrigerant and excess oil in the system.  
							

								When an installation technician does not know the exact amount of refrigerant required, the tank serves as a safety reserve for the entire refrigeration system.
							

								The tank is used to store and ensure an adequate supply of refrigerant in the event of fluctuations in the thermal load of the refrigeration system.
							

39 Stredne ťažká

What is the purpose of the liquid refrigerant reservoir?

								The tank is required during maintenance work, when there is a temporary need to store the refrigerant that has been circulating in the refrigeration system up to that point.
							

								When an installation technician does not know the exact amount of refrigerant required, the tank serves as a safety reserve for the entire refrigeration system.
							

								The tank is used to collect the liquid refrigerant and excess oil in the system.  
							

								The tank is used to further cool the liquefied refrigerant leaving the condenser.
							

40 Stredne ťažká

Where should the liquid receiver be installed?

It should be fitted between the compressor and the condenser.

								 It should be installed downstream of the condenser, upstream of the expansion valve.
							

It should be fitted after the evaporator.

It should be fitted just before the compressor.

41 Stredne ťažká

What is the function of the suction pressure regulator fitted to the suction pipe when the compressor starts up?

It closes when the suction pressure upstream of the compressor drops.

It regulates the condensing pressure.

It opens when the suction pressure upstream of the compressor drops.

It regulates the evaporation pressure.

42 Stredne ťažká

The use of microchannel heat exchangers, compared with conventional heat exchangers made of copper tubes and fins, results in:

A reduction in the amount of refrigerant and an increase in energy efficiency.

								There is no effect whatsoever on either the amount of refrigerant or energy efficiency.
							

A reduction in the system’s energy efficiency.

								An increase in the amount of refrigerant in the system and an increase in condensing pressure.
							

43 Stredne ťažká

Which refrigerants belong to the HFC group?

R134a, R404A, R507A, R410A.

R11, R12, R502.

R22, R401A.

R134a, R32, R22, R507A, R290.

44 Stredne ťažká

Which refrigerants belong to the HFO group?

R134a, R404A.

R134a, R290.

R22, R12.

R1234yf, R1234ze.

45 Stredne ťažká

What are the characteristics of R410A refrigerant compared to R407C refrigerant?

The saturation pressure of R407C is 150% higher than that of R410A.

The saturation pressure of R410A refrigerant is higher than that of R407C.

The saturation pressure of both refrigerants is roughly the same.

The saturation pressure of R407C refrigerant is much higher than that of R410A.

46 Stredne ťažká

What does the TEWI parameter define?

								It is the total (global) greenhouse gas equivalent – this indicator takes into account the refrigerant’s direct capacity to contribute to the greenhouse effect and its indirect impact on it through the energy consumption (during the production of which CO₂ is generated) by the refrigeration unit in operation.
							

								This is a parameter defining the ozone layer’s ability to recover (regenerate).
							

								This is a parameter that quantifies the impact of refrigerants on the ozone layer.
							

								It is the global warming potential, expressed in terms of carbon dioxide (CO₂), over a 100-year time horizon.
							

47 Stredne ťažká

What are the characteristics of R452A refrigerant compared to R404A?

Both refrigerants are homogeneous refrigerants with no temperature glide.

It is a flammable and toxic homogeneous refrigerant from the HFC group.

								It is a non-flammable refrigerant, a mixture from the HFC/HFO group with thermodynamic properties similar to those of R404A and a GWP approximately 45% lower than that of R404A.
							

The temperature glide of R452A is half that of R404A.

48 Stredne ťažká

What is the distinguishing feature of R1234yf compared to R134a?

A higher critical temperature.

greater flammability.

greater toxicity.

a higher boiling point at standard pressure.

49 Stredne ťažká

Compared to R134a, the refrigerant CO₂ is characterised by?

Unlike R134a, it is an azeotropic mixture.

								 It has identical thermodynamic properties and can be used as a drop-in replacement for R134a.
							

It has a temperature slip of 7K greater than R134a.

								It has a lower critical temperature, higher operating pressures and greater volumetric efficiency, allowing for the use of a smaller quantity of refrigerant compared to R134a. 
							

50 Stredne ťažká

The following are not classified as fluorinated greenhouse gases:

Sulphur hexafluoride (SF6).

Perfluorocarbons (PFCs).

Carbon dioxide (CO₂).

Hydrofluorocarbons (HFCs).

51 Ťažká

What additional protective equipment will you use when soldering systems containing HC refrigerants?

Fire blanket

High-visibility jacket

Flammable gas detector

Tinted safety goggles

52 Ťažká

Why can’t a sealed high-pressure switch be replaced with a standard mechanical one in a system containing a flammable refrigerant?

The pressure switch setting will not be correct

Dust and moisture may enter

There is a risk of refrigerant leakage

It is a potential source of ignition

53 Ťažká

What is the minimum distance from the work area where HC refrigerants are used at which there must be no sources of ignition?

3 m

2 m

0.5 m

1 m

54 Ťažká

What is the maximum safe charge for a recovery cylinder with R32 refrigerant, if it can be charged with 20 kg of R410A?

9 kg

33 kg

18 kg

20 kg

55 Ťažká

According to EN 378, what is the maximum charge of an A3 refrigerant for a display unit (hermetic, with an internal condenser) located in the ground-floor retail area of a supermarket?

1.5 kg

2.5 kg

1.0 kg

10 kg

56 Ťažká

How can a vacuum pump be used safely to evacuate a system containing a flammable refrigerant?

Position the vacuum pump 3 metres above floor level

There is no need to evacuate such systems

Use an ATEX-certified vacuum pump in a well-ventilated area

Fit a long hose to the pump outlet to remove HC away from the system

57 Stredne ťažká

What is the greenhouse effect?

								It causes the thermal radiation emitted by the Earth to be trapped in the upper atmosphere.
							

It alters the composition of the atmospheric air.

It lowers the average surface temperature of the Earth.

								It causes an increase in temperature close to the Earth’s surface (up to 10 metres above the surface).
							

58 Ťažká

What protective equipment must you have in your car when transporting flammable substances?

A fire extinguisher

Fire blanket

Thick gloves

Tinted safety goggles

59 Ťažká

How would you remove the refrigerant from a 10kg R32 water chiller, located outdoors, before unsoldering the connections?

								Vent the R32 to the outside; charge the system with nitrogen until an overpressure is achieved, vent and drain the system twice, charge the system with nitrogen a third time and vent
							

Vent the R32 to the outside and drain the system

								Recover the R32 until a vacuum is achieved, then charge the system with nitrogen to a relative pressure of 0.1 bar g
							

Recover the R32 until a vacuum is achieved

60 Stredne ťažká

What is R1270?

Propene

Isobutane

Butane

Propene

61 Ťažká

Which of the following leak detection methods cannot be used to locate an HC refrigerant leak?

Electronic leak detector for flammable refrigerants

Electronic HFC leak detector

Soapy water solution

Leak detection foam

62 Ťažká

What is the most important difference between a flammable refrigerant recovery unit and a standard one?

Different low-pressure switch setting

Different connection sizes

A flammable refrigerant recovery unit has no ignition sources

A different colour for the station

63 Ťažká

Which of the following is a source of ignition?

‘n’ type thermostat

Ex-certified evaporator fan motor

Defrost heating element

Contactor

64 Ťažká

What substance is produced when R32 is burnt?

Hydrochloric acid

Phosgene

Carbon monoxide

Hydrogen fluoride

65 Ťažká

What type of refrigerant is R1234ze?

Hydrofluoroolefin

Chloro-fluoro-hydrocarbon

Hydrocarbon

Hydrochlorofluoro-hydrocarbon

66 Ťažká

What hazards does a Group A3 refrigerant pose?

Low toxicity, moderate flammability

High toxicity, high flammability

Low toxicity, highly flammable

High toxicity, moderate flammability

67 Ťažká

According to EN 378, what is the maximum charge of R290 in a cold store measuring 5 m x 3 m x 2.5 m in height (the LFL for R290 is 0.038 kg/m³)?

4.93 kg

1.5 kg

1.0 kg

0.285 kg

68 Ľahká

What does the GWP indicator mean?

It is a unit expressing the ability to enhance the ozone layer.

								It is the global warming potential. The impact on global warming caused by 1 kg of a given gas or chemical substance, expressed as a GWP value, where GWP=1 represents the global warming caused by 1 kg of CO₂ over a period of 100 years (the global warming potential of a unit mass of a given gas over a 100-year period, relative to the warming caused by a unit mass of CO₂).
							

								It is an expansion of the abbreviation ‘Global Warming Potential’ and indicates the rate of increase in air temperature 
							

This is an indicator expressing the potential to deplete the ozone layer.

69 Ťažká

What is the cooling capacity of R32 compared to R410A?

60%

75%

130%

105%

70 Ťažká

Why are Ex-certified evaporator fan motors used in some systems with flammable refrigerants?

								Because they must be kept running continuously to disperse the leaking refrigerant
							

Because they are more energy-efficient

Because they are more reliable

To avoid a source of ignition in the event of a flammable refrigerant leak

71 Ťažká

Why is the difference in density between HC and HFC refrigerants important?

Because it affects energy efficiency

Because it affects the charging rate

Because it increases operating pressures

Because it affects the charge weight

72 Ťažká

What is the GWP value for R290?

7

675

3

A. 0.02

73 Ťažká

Which of the following is not a source of ignition?

An Ex-certified fan motor

Electrical switch

Open mechanical pressure switch

Light switch

74 Ťažká

What is R290?

Propene

Propylene

Butane

Propene

75 Ťažká

According to EN 378, what is the maximum HC refrigerant charge for a display unit (hermetic system with an internal condenser) located in the ground-floor shopping area of a supermarket?

150 g

2.5 kg

1.0 kg

1.5 kg

76 Ťažká

Why can’t a standard relay be fitted when retrofitting a compressor’s electrical system for flammable refrigerants?

It could be a source of ignition

								Current consumption differs for compressors using flammable refrigerants compared to those using HFCs
							

The method of starting the compressor motor differs from that used with HFCs

A relay is never required for compressors using flammable refrigerants

77 Ťažká

What is the minimum distance from the work area where HC refrigerants are used at which there must be no sources of ignition?

3 m

1 m

5 m

10 m

78 Ťažká

What is the safe charge for a recovery cylinder with R290 refrigerant, if it can be charged with 10 kg of R404A?

20 kg

17 kg

8 kg

3.6 kg

79 Stredne ťažká

How do refrigeration systems contribute to the greenhouse effect, i.e. the rise in atmospheric temperature at the Earth’s surface?

								As a result of oil being emitted into the atmosphere by the condenser and filter
							

Through the leakage of refrigerant into the environment.

								Indirectly (through energy consumption) and directly (through the emission of refrigerants into the atmosphere)
							

Refrigeration equipment emits CO₂ both directly and indirectly.

80 Ťažká

How can a vacuum pump be used safely to evacuate a system containing R290?

There is no need to evacuate systems containing R290

Use an ATEX-certified vacuum pump in a well-ventilated area

Position the vacuum pump 3 metres above floor level

Fit a long hose to the pump outlet to remove HC away from the system

81 Ťažká

In accordance with ADR regulations, what protective equipment must you have in your vehicle when transporting flammable refrigerants?

A fire extinguisher

Thick gloves

Fire blanket

Tinted safety goggles

82 Ťažká

How do you ensure it is safe to light the torch needed to desolder joints in a system that has been evacuated of flammable refrigerant?

								You must not desolder joints on a system containing a flammable refrigerant; they must be cut using a pipe cutter
							

Work outdoors

								Ensure the area is well ventilated and use a flammable gas detector to check the area
							

Purge the system with oxygen-free nitrogen

83 Ťažká

How would you remove the refrigerant from a system containing 100 g of R1270 so that it is ready for the joints to be desoldered?

Vent the R1270 to the outside and drain the system

								Recover the R1270 until a vacuum is achieved, then charge the system with nitrogen to a relative pressure of 0.1 bar g
							

Recover the R1270 until a vacuum is achieved

								Vent the R1270 to the outside; charge the system with nitrogen until an overpressure is reached, vent and evacuate the system twice, charge the system with nitrogen a third time and vent 
							

84 Ťažká

Which of the following leak detection methods cannot be used to locate a leak of R290 refrigerant?

Electronic HFC leak detector

Fluorescent dye and a UV lamp

Electronic leak detector for flammable refrigerants

Leak detection foam

85 Ťažká

Why can’t recovery stations designed for HFCs be used with R600a?

								The low-pressure switch setting will not be suitable for R600a due to its lower operating pressure
							

It contains ignition sources

The oil in the recovery unit is not soluble in R600a

The recovery unit cannot withstand the working pressure of R600a

86 Ťažká

According to EN 378, what is the maximum charge of R1234ze in a cold store measuring 5 m x 3 m x 2.5 m in height (the LFL for R1234ze is 0.303 kg/m³)?

227 kg

2.27 kg

6.18 kg

618 kg

87 Ťažká

What type of refrigerant is R32?

Hydrocarbon

Carbon dioxide

Hydrofluorocarbon

Hydrofluoroolefin

88 Ťažká

What hazards do A2L refrigerants pose?

Low toxicity, high flammability

High toxicity, high flammability

High toxicity, moderate flammability

Low toxicity, moderate flammability

89 Ťažká

What danger is associated with the combustion of HFO or HFC refrigerants?

Phosgene is produced

Nitrous oxide is produced

Citric acid is produced

Hydrogen fluoride is produced

90 Stredne ťažká

What is the greenhouse effect, also known as the greenhouse phenomenon?

The absorption of radiation reaching the Earth’s surface.

								It is the phenomenon of heat being trapped in the Earth’s atmosphere (making it difficult for heat to radiate out of the Earth’s atmosphere).  
							

								This is the formation of a layer that traps only the heat generated by the combustion of fuel in aeroplanes.
							

The filtering out of solar radiation.

91 Ťažká

What is the approximate displacement volume required for a compressor running on R600a compared to one running on R134a to achieve the same cooling capacity?

Twice

The same

Half

Seven times

92 Ťažká

What is the GWP value for R32?

675

3

7

0

93 Ťažká

Why is the accuracy of the charge weight more important for systems critically charged with R290 compared to those using HFCs

Due to lower operating pressures

Because these systems never have liquid receivers

Because R290 is only used in systems with a charge of less than 150g

								The charge mass is significantly lower than in an HFC system, as the density is much lower
							

94 Ťažká

Why does the condenser fan run continuously in some systems using R1270?

To prevent the build-up of contaminants in the condenser

To reduce energy consumption

To ensure that the discharge pressure never becomes excessive

To dilute the refrigerant in the event of a leak

95 Stredne ťažká

Which EU regulation is currently the primary piece of legislation governing the use of fluorinated greenhouse gases (F-gases) in the European Union?

Regulation (EU) 2024/573

Directive 2009/125/EC

Regulation (EU) No 517/2014

Regulation (EU) 2015/1188

96 Stredne ťažká

What is the main objective of Regulation (EU) 2024/573?

To facilitate the import of electrical appliances

Standardising metal recycling standards

Prevention of F-gas emissions and the achievement of the EU’s climate targets

To reduce taxes on refrigeration equipment

97 Stredne ťažká

What are the obligations of manufacturers of refrigeration appliances in the context of ecodesign, and which regulation governs them?

								Manufacturers are only required to use energy labels, and this is regulated by Regulation (EU) 2024/573
							

								Manufacturers must comply solely with ISO 9001 standards, without any link to EU regulations
							

								The manufacturer must ensure minimum energy efficiency, reparability and recyclability of equipment, as regulated by Regulation (EU) 2019/2019 
							

								Manufacturers are only required to declare the quantity of F-gas used, in accordance with Regulation (EU) No 517/2014
							

98 Stredne ťažká

What is the main objective of the Ecodesign Directive?

To facilitate the import of products from outside the EU

To standardise the appearance of products in the EU

								Reducing the negative environmental impact of products by improving energy efficiency, durability and recyclability 
							

To increase sales of electrical appliances in the EU

99 Stredne ťažká

What is the function of a ball valve in a refrigeration system?

It regulates the temperature of the refrigerant

It prevents excessive pressure build-up in the system

It measures the moisture content of the refrigerant

Enables the refrigerant flow to be completely shut off

100 Ľahká

What is the main function of a relief valve?

Relieves pressure in the system in the event of excessive pressure

It monitors the moisture content of the refrigerant

It controls the oil level in the compressor

Prevents the evaporator from freezing

101 Stredne ťažká

How do certain substances or gases contribute to the greenhouse effect?

								Certain substances trap the thermal radiation that the Earth should radiate into the atmosphere. In this way, the Earth gradually warms up and the greenhouse effect occurs.  
							

Some substances damage the ozone layer

								When released into the atmosphere, certain substances cause the air to heat up as a result of reactions with the oxygen and nitrogen contained in the air.
							

								Certain substances limit the impact of the Sun’s ultraviolet radiation on the Earth’s surface.
							

102 Stredne ťažká

What is the purpose of the sight glass in a refrigeration system?

To shut off the flow in the event of an emergency

								For visual assessment of the presence of refrigerant and oil, and for monitoring moisture levels 
							

To measure the condenser temperature

To regulate compressor pressure

103 Stredne ťažká

What is the function of the temperature regulator in a refrigeration system?

It restricts oil flow

It drains excess refrigerant into the receiver

								Controls the operation of the compressor and valves to maintain the set temperature 
							

To maintain a constant pressure in the compressor

104 Ťažká

What is the role of the liquid separator in systems using flammable or toxic refrigerants?

Heats the refrigerant before it enters the evaporator

It prevents liquid from entering the compressor

It separates the liquid from the oil

They are used solely to measure the moisture content of the refrigerant

105 Ťažká

What is the function of an oil separator in systems using flammable or toxic refrigerants?

It prevents liquid from entering the compressor

They are used solely to measure the moisture content of the refrigerant

								Separates oil from the refrigerant and facilitates the return of oil to the compressor
							

Heats the refrigerant before it enters the evaporator

106 Stredne ťažká

What is the purpose of oil level regulators in a refrigeration system?

They control the evaporator temperature

They drain off excess refrigerant

Maintains the correct oil level in the compressor

They control the pressure in the condenser

107 Stredne ťažká

What is the function of the refrigerant receiver in the system?

Stores excess refrigerant and facilitates the detection of leaks

Regulates the oil flow

It maintains a constant pressure in the system

It controls the evaporator temperature

108 Stredne ťažká

What is the role of the manifold thermometer in the refrigeration system?

Relieves pressure in the system in the event of excessive pressure

								Measures the refrigerant temperature at the compressor inlet and outlet, which helps to identify leaks 
							

It monitors the moisture content of the refrigerant

Controls the oil level

109 Stredne ťažká

What is the role of the defrost control valves?

They are used to monitor the moisture content of the refrigerant

They control the pressure in the compressor

Protect the evaporator from excessive icing and reduce the risk of leaks

They drain off excess oil

110 Ťažká

Why do CO₂ refrigeration systems require special attention when separating liquid and oil?

								CO₂ operates at high pressure, which increases the risk of compressor failure and leaks 
							

CO₂ cannot be used in systems with sight glasses

CO₂ is flammable, so separators cannot be used

CO₂ does not require lubrication, so separators are unnecessary

111 Ťažká

What is the critical pressure of CO₂ (R744)?

Approximately 10 bar

Approximately 31 bar

Approximately 74 bar

Approximately 120 bar

112 Ľahká

What is the base unit of pressure according to the International System of Units (SI)?

Atm.

Psi

Pa

bar

113 Stredne ťažká

Where can I find lists detailing fluorinated greenhouse gases (F-gases)?

In the Vienna Convention for the Protection of the Ozone Layer.

								In the Act on Ozone-Depleting Substances and Certain Fluorinated Greenhouse Gases.
							

								In the Regulation of the Minister for the Economy on the introduction of a list of fluorinated greenhouse gases.
							

In Regulation (EU) No 2024/573 of the European Parliament and of the Council

114 Ťažká

What characterises the transcritical process in CO₂ systems?

Conventional condensation occurs

								The system operates above the critical point and the refrigerant does not condense in the conventional manner 
							

It is irrelevant to the operation of the system

It occurs only at low temperatures

115 Ťažká

What characterises the subcritical CO₂ process?

The absence of evaporation

The conventional condensation process below the critical point

Operation above the critical point

The absence of condensation

116 Ťažká

What is the log(p)-h diagram for CO₂ used for?

To measure temperature

To detect leaks

To regulate pressure

For analysing thermodynamic processes in a refrigeration system

117 Ťažká

What can be read from the log(p)-h graph?

Only the humidity

Pressure, enthalpy, temperature and state of the refrigerant

Only the temperature

Only the amount of refrigerant

118 Ťažká

What are CO₂ saturation tables used for?

To determine the oil quantity

To measure humidity

To determine the relationship between temperature and pressure at saturation

To regulate the compressor

119 Ťažká

What does the CO₂ saturation state mean?

Equilibrium between the liquid and vapour phases

Dry ice state

A state in which the refrigerant is only a gas

A state of high pressure

120 Ťažká

When can dry ice (solid CO₂) form?

At high temperature

During normal operation of the system

								In the event of a sudden drop in pressure and temperature below the triple point 
							

At high pressure

121 Ťažká

What risks are associated with the formation of dry ice in a CO₂ system?

No risk

Pressure reduction

Blocked pipes and system damage

Improved efficiency

122 Ťažká

How does the CO₂ pressure change as the temperature rises?

Rises sharply

It remains the same

It decreases

It first decreases, then increases

123 Ťažká

Why is understanding the log(p)-h graph particularly important for CO₂?

It is only used for design purposes

								As CO₂ systems operate in different modes (sub- and transcritical) and require detailed analysis 
							

It only applies to NH₃

It doesn’t matter

124 Stredne ťažká

Where can I find the lists specifying controlled substances?

In the Vienna Convention for the Protection of the Ozone Layer.

								In the Regulation of the Minister for the Environment on the list of controlled substances.
							

								In the current Act on Ozone-Depleting Substances and Certain Fluorinated Greenhouse Gases.
							

In Regulation (EU) No 2024/590 of the European Parliament and of the Council.

125 Ťažká

What happens to CO₂ above the critical point?

It ceases to conduct heat

It transitions to a supercritical state (no distinction between liquid and gas)

It turns into a solid

It turns into a liquid

126 Ťažká

Why do CO₂ systems require precise pressure control?

Due to low pressures

They do not require control

Because there are no valves

Due to significant pressure changes with temperature fluctuations

127 Stredne ťažká

Why is ammonia (NH₃) considered a toxic refrigerant?

It is flammable and can form explosive mixtures with air

It is colourless and odourless, so it is difficult to detect

It does not react with water, which makes it difficult to neutralise

It is highly irritating to the respiratory tract and toxic if inhaled

128 Ťažká

What is the main difference between a dry evaporator and a flooded evaporator?

								A dry evaporator allows the entire refrigerant to evaporate in the pipe upstream of the compressor; in a flooded evaporator, part of the refrigerant remains in a liquid state within the evaporator 
							

A dry evaporator has a lower operating pressure than a flooded one

								A dry evaporator is filled with refrigerant liquid, whilst a flooded evaporator is filled with gas
							

								A dry evaporator does not require an expansion valve, whereas a flooded one does
							

129 Ťažká

What is the typical pressure in deep-freezing systems (below −40 °C) for an evaporator in a system using R717?

A pressure varying between 10 and 20 bar

Negative pressure (vacuum), below 0 bar

Atmospheric pressure, approximately 1 bar

Positive pressure, in the range of 5–10 bar

130 Ťažká

Why are PFAS substances formed as a result of the decomposition of certain F-gases problematic?

								They are readily biodegradable, so they only pollute the environment for a short time
							

They are climate-neutral

They cause rapid cooling of the atmosphere

They are persistent, accumulate in the environment and may be toxic

131 Ťažká

What is the basic requirement when charging a system with R717 (NH₃)?

Charging must only take place at temperatures below 0°C

NH₃ can be charged together with air

								Charging should take place in a well-ventilated area using appropriate personal protective equipment 
							

Charging can be carried out without personal protective equipment

132 Ťažká

How should oil be handled in systems using R717?

Oil has no effect on the system’s operation

Oil can be mixed with any refrigerant

								The oil should be checked regularly and any excess removed from the lower parts of the units to prevent reduced heat transfer and leaks 
							

The oil does not require any monitoring

133 Ťažká

What is the correct procedure for recovering R717 from a system?

								The refrigerant must be recovered into suitable, leak-proof tanks designed for NH₃ 
							

The gas can be released into the atmosphere

Recovery is not required

The refrigerant can be drained into the sewer system

134 Ťažká

How should R717 (NH₃) be stored?

In any open containers

In sealed, labelled containers, in a cool and well-ventilated place

Near heat sources

In unmarked plastic containers

135 Stredne ťažká

Where and by when should annual reports on ODS and F-gases be submitted?

								Reports must be submitted by the end of the relevant calendar year, using a special form at the regional branch of the Office of Technical Inspection (UDT)
							

								Reports for the previous year must be submitted by 31 January electronically by completing the special forms available in the central register of operators ‘CRO’.
							

								Reports for the previous year must be submitted by 31 March of the relevant year electronically to the Ministry of the Environment.
							

								Reports on ODS and F-gases for the previous year must be submitted by 28 February of the following year, via the IT system available in the reports database at the Office for the Protection of the Ozone Layer and Climate (BOWOiK) on the ICHP website. 
							

136 Ťažká

What should be done in the event of R717 contamination?

Continue to use without restriction

								The refrigerant must be purified or sent for disposal in accordance with regulations 
							

Add water to dilute it

Release into the atmosphere

137 Ťažká

What is the main hazard associated with an R717 leak during maintenance work?

No risk whatsoever

Damage to electrical equipment only

Toxic to humans and may cause chemical burns

Increased cooling efficiency

138 Ťažká

What action should be taken if an NH₃ leak is detected?

Increase the pressure in the system

Ignore it and carry on working

								Evacuate personnel immediately and remove the source of the leak, if it is safe to do so 
							

Close your eyes and carry on working

139 Ťažká

What role do scrubbers play in NH₃ systems?

They store the refrigerant

They increase the pressure in the system

Neutralises ammonia through absorption in a liquid (e.g. water)

They are used to measure temperature

140 Ťažká

How should the system be prepared before filling with R717?

There is no need to check it

Simply start it up

Check for leaks, remove air and moisture, and create a vacuum

The pressure must be increased above the standard level

141 Ťažká

What are the transport requirements for R717?

Transport is not subject to regulations

								Must be transported in suitable, labelled containers in accordance with ADR regulations 
							

It can be transported in open containers

It can be transported without labelling

142 Ťažká

What personal protective equipment is required when working with NH₃?

No requirements

Only a safety helmet

Workwear only

Safety goggles, gloves and respiratory protective equipment

143 Stredne ťažká

Which measure has the greatest impact on improving the compressor’s energy efficiency during installation?

Installation without filters

Correctly create a vacuum and remove moisture from the system

Installation without a leak test

Increasing the amount of refrigerant

144 Stredne ťažká

How does regular monitoring of the oil level affect the compressor’s operation?

It reduces cooling capacity

It has no effect

Causes a rise in pressure

Ensures proper lubrication and improves energy efficiency

145 Stredne ťažká

How do system leaks affect the compressor’s energy efficiency?

These cause a drop in performance and an increase in energy consumption

They lower the operating temperature

Have no effect

They improve efficiency

146 Stredne ťažká

Regulation (EC) No 2024/590 relates to:

Health and safety at work during the recovery of refrigerants.

								The conditions for obtaining F-gas certificates by companies carrying out the recovery and reclamation of waste refrigerants.
							

Ozone-depleting substances.

								Alternative refrigerants serving as substitutes for fluorinated greenhouse gases.
							

147 Stredne ťažká

What is the significance of regulating suction and discharge pressure?

Causes leaks

Helps maintain optimal operating conditions for the compressor

Increases oil consumption

It has no effect on efficiency

148 Stredne ťažká

What maintenance measure reduces the compressor’s energy consumption?

Lack of servicing

Increasing the refrigerant charge

Regular replacement of filters and dryers

Disabling safety devices

149 Stredne ťažká

How does the presence of air in the refrigeration system affect performance?

It has no effect

Leads to increased pressure and reduced efficiency

Reduces energy consumption

It improves efficiency

150 Stredne ťažká

What role do control systems (e.g. regulators) play in compressor efficiency?

Causes leaks

It doesn’t matter

Enables optimisation of operation and a reduction in energy consumption

It increases the amount of refrigerant

151 Stredne ťažká

How does refrigerant superheat at the compressor suction affect performance?

Excessive overheating reduces efficiency and increases energy consumption

It always improves performance

It only causes a drop in temperature

It has no effect

152 Stredne ťažká

How does the correct layout of the system affect efficiency?

Shortens flow paths and reduces energy losses

It increases the pressure

It doesn’t matter

It causes the temperature to rise

153 Stredne ťažká

How important is pipe insulation?

Reduces heat loss and improves energy efficiency

Causes a rise in pressure

It increases energy consumption

It has no effect

154 Stredne ťažká

Which measure most improves the condenser’s energy efficiency?

Restricted airflow

Contamination of the heat exchange surface

Increasing the amount of refrigerant

Regular cleaning of heat exchange surfaces

155 Stredne ťažká

How does a dirty condenser affect the operation of the refrigeration system?

It has no effect

It improves efficiency

Causes an increase in pressure and energy consumption by the compressor

It lowers the condensing pressure

156 Stredne ťažká

Why is adequate airflow through an air-cooled condenser important?

Causes a drop in pressure

Ensures effective heat dissipation and improves energy efficiency

It doesn’t matter

Insufficient airflow reduces efficiency

157 Stredne ťažká

Which refrigerants cause damage to the ozone layer?

All refrigerants that contain chlorine or bromine in their molecules.

All refrigerants that are hydrocarbon derivatives.

All refrigerants that contain carbon in their molecular structure.

All refrigerants that contain fluorine and hydrogen in their molecules.

158 Stredne ťažká

How does the presence of limescale in a water-cooled condenser affect performance?

Impairs heat exchange and increases energy consumption

It lowers the condensation temperature

It improves heat transfer

It has no effect

159 Stredne ťažká

How does correct condensation pressure control affect efficiency?

Maintains optimum operating conditions and reduces energy consumption

Causes leaks

It increases energy consumption

It has no effect

160 Stredne ťažká

How do condenser leaks affect energy efficiency?

Have no effect

They improve efficiency

They lower the temperature

Causes refrigerant loss and a drop in efficiency

161 Stredne ťažká

How important is the correct positioning of an air-cooled condenser?

It should be installed in a well-ventilated area with unobstructed airflow

It should be housed in a small room

It should be close to heat sources

It doesn’t matter

162 Stredne ťažká

How does hot air recirculation affect the condenser?

It reduces the pressure

It improves efficiency

It has no effect

Impairs cooling and increases energy consumption

163 Stredne ťažká

How does the insulation of central heating and domestic hot water pipework affect the operation of the heat pump’s condenser?

Reduces energy losses and improves the efficiency of the entire system

It increases the pressure

It impairs cooling

It doesn’t matter

164 Stredne ťažká

Which measure most improves the energy efficiency of the evaporator?

Increasing the condensation temperature

Regular defrosting of the evaporator

Increasing the amount of refrigerant

Restricted airflow

165 Stredne ťažká

How does evaporator icing affect the system’s operation?

It lowers the condensation temperature

It has no effect

It improves cooling performance

Impairs heat exchange and increases energy consumption

166 Stredne ťažká

How does dirt on the evaporator surface affect its performance?

It reduces the pressure

It has no effect

It improves efficiency

Impairs heat exchange and increases energy consumption

167 Stredne ťažká

What maintenance task is crucial for the evaporator?

Lack of maintenance

Regular cleaning and defrosting

Increasing the refrigerant charge

Reduced airflow

168 Stredne ťažká

What does an F-gas personal certificate (Category A2) authorise?

								for the purchase of lubricants and refrigeration oils, and for the testing of safety valves.
							

								to make permanent joints by brazing in systems containing fluorinated greenhouse gases.
							

								to repair, maintain or service refrigeration equipment and systems containing controlled substances.
							

								To recover refrigerant from equipment containing less than 3 kg of fluorinated greenhouse gases, or less than 6 kg in the case of hermetically sealed systems.
							

169 Stredne ťažká

How does superheating of the refrigerant at the evaporator outlet affect efficiency?

It has no effect

It always improves performance

It only causes a drop in temperature

Excessive superheat reduces energy efficiency

170 Stredne ťažká

How do leaks in the evaporator affect efficiency?

These cause refrigerant loss and a drop in efficiency

Have no effect

Improves performance

Increase capacity

171 Stredne ťažká

How important is correct expansion valve adjustment?

It doesn’t matter

It increases energy consumption

Ensures optimal evaporator charge and improves efficiency

Causes leaks

172 Stredne ťažká

How does inadequate insulation of the heat transfer circuit pipes affect evaporator performance?

It improves efficiency

It has no effect

It lowers the condensation temperature

Causes cooling losses and increased energy consumption

173 Stredne ťažká

How does correct TEV valve adjustment affect the system’s energy efficiency?

Ensures optimum superheat and improves system efficiency

Causes leaks

It has no effect

It increases energy consumption

174 Stredne ťažká

What happens if the superheat set by the TEV is too high?

Cooling efficiency will improve

Efficiency will drop because the evaporator is not being fully utilised

It has no effect

The refrigerant charge will increase

175 Stredne ťažká

How does a low superheat setting on the TEV affect performance?

It has no effect

It increases operational safety

It reduces refrigerant flow

								It may lead to improved efficiency, but it increases the risk of the compressor becoming flooded with liquid 
							

176 Stredne ťažká

How do contaminants in the system affect the operation of the TEV?

Have no effect

They improve its performance

They can cause it to become blocked and reduce efficiency

They lower the temperature

177 Stredne ťažká

What role does the filter-drier play in terms of system efficiency?

It lowers the temperature

Removes moisture and contaminants, improving the system’s efficiency

It increases the amount of refrigerant

It doesn’t matter

178 Stredne ťažká

How does proper insulation of components (e.g. pipes near the TEV) affect the system?

It causes leaks

Prevents unwanted heat gains and improves efficiency

It increases energy consumption

It doesn’t matter

179 Stredne ťažká

What does Regulation (EU) No 2024/573 of the European Parliament and of the Council cover?

The Regulation sets out health and safety requirements for soldering work.

The Regulation concerns gases that contribute to the greenhouse effect.

								The Regulation sets out requirements relating to brazing of refrigeration systems.
							

								The Regulation concerns leak testing of stationary refrigeration, air-conditioning and heat pump equipment containing fluorinated greenhouse gases. The Regulation sets out the requirements relating to leak testing of such equipment.
							

180 Stredne ťažká

How important is it to check the operation of the condensing pressure control valve in the system?

Ensures operation within the optimum pressure range and reduces energy losses

It increases energy consumption

It causes a significant rise in temperature

It has no effect

181 Stredne ťažká

How does the correct selection of a TEV affect energy efficiency?

Ensures the system is matched to its capacity and operates optimally

It increases the amount of refrigerant

It lowers the temperature

It doesn’t matter

182 Stredne ťažká

What is the main design difference in hydrocarbon-based refrigeration systems?

Higher operating pressures

No need for safety measures

Lower energy efficiency

								The need for explosion-proof measures due to the flammability of the refrigerant 
							

183 Stredne ťažká

What differences are there in the compressors used in hydrocarbon systems?

They do not require lubrication

No differences

They must operate at higher pressures

								They must be designed to operate with flammable refrigerants (e.g. hermetic compressors) 
							

184 Ťažká

What is the main characteristic of R744 (CO₂) refrigeration systems?

Low operating pressures

No need for regulation

Low energy efficiency

Very high operating pressures

185 Ťažká

What are the requirements for piping materials in CO₂ systems?

They must be made exclusively from plastics

They may be made of any material

They must be able to withstand high pressures (e.g. high-grade steel)

It does not matter

186 Ťažká

How does a booster system work in CO₂ installations?

It reduces the amount of refrigerant

It reduces the pressure in the evaporator

								It utilises two stages of compression (low and medium pressure) in a single system 
							

It is used to store the refrigerant

187 Ťažká

What is the function of high-pressure control valves in CO₂ systems?

								They control the pressure on the high-pressure side and optimise system operation 
							

They lower the evaporator temperature

They are used to store the refrigerant

They regulate oil flow

188 Ťažká

Why is pressure optimisation in CO₂ systems crucial?

It doesn’t matter

It reduces the ambient temperature

It reduces the amount of refrigerant

It enables the system to achieve maximum energy efficiency

189 Ťažká

What role do parallel-operating compressors play in CO₂ systems?

It does not matter

They increase energy consumption

They lower the ambient temperature

They enable gas recovery from the medium-pressure stage and improve efficiency

190 Stredne ťažká

How can one check whether the system has been overcharged with refrigerant?

								This cannot be checked with sufficient reliability, as the sight glass is not designed for this purpose.
							

								The refrigeration system is overcharged with refrigerant whilst in operation, and even under a very small heat load, frost forms on the suction side of the compressor 
							

								Under normal conditions, there is a marked increase in condensing pressure because an excessive amount of refrigerant accumulates in the condenser, reducing the heat exchange surface area within it.
							

								The compressor will operate under a lower load and the suction pressure will decrease
							

191 Ťažká

How does an ejector work in a CO₂ system?

It lowers the evaporator temperature

Stores the refrigerant

								It uses the energy of the higher-pressure refrigerant to raise the pressure of the refrigerant from the lower stage, which improves efficiency 
							

It increases the amount of refrigerant

192 Ťažká

What is the function of liquid ejectors in CO₂ systems?

They assist with liquid recovery and improve evaporator feed

They raise the refrigerant temperature

They reduce atmospheric pressure

They increase the amount of oil

193 Ťažká

What are the characteristics of partially flooded systems in CO₂ systems?

Low operating pressure

The absence of liquid in the evaporator

Lack of regulation

								The presence of liquid in the evaporator, which improves heat transfer and efficiency 
							

194 Ťažká

What is the main risk associated with static pressure in CO₂ systems?

A drop in temperature

A decrease in refrigerant quantity

A rise in pressure resulting from the refrigerant heating up whilst at rest

Increased efficiency

195 Ťažká

How can standstill pressure in CO₂ systems be reduced?

By increasing the refrigerant charge

By shutting down the system completely

By using parallel compressors and external cooling systems

By increasing the temperature

196 Ťažká

What does ‘stagnation’ of a refrigeration system mean in the context of CO₂?

Improved efficiency

Normal system operation

A drop in temperature

								A lack of refrigerant flow, which can lead to increased pressure and safety risks 
							

197 Ťažká

Why do CO₂ systems require more advanced automation than traditional systems?

Due to the need for precise control of pressure and temperature

Due to low pressures

They do not require automation

Because there are no valves

198 Ťažká

What must be included on the label of a cylinder containing a flammable refrigerant?

Information about the cylinder owner

The name of the refrigerant, the hazard symbol and basic safety information

Agent name only

Net weight only

199 Ťažká

Why does the absence of a ‘flammable agent’ label on the system pose a significant hazard?

It may lead to the incorrect selection of oil

It has no significant impact on safety

It may lead to the use of tools that are a source of ignition

It reduces the system’s efficiency

200 Ťažká

Which set of information on the label of a flammable agent cylinder is crucial from a safety perspective?

Cylinder colour and date of manufacture

Gross weight and batch number

Manufacturer’s name and country of origin

Name of the substance, hazard pictogram, UN number

201 Stredne ťažká

Before charging the refrigeration unit with refrigerant, it is essential to…

complete the unit’s data sheet.

carry out a start-up test.

check the compressor’s suction and discharge connections.

carry out a leak test.

202 Ťažká

What is the requirement regarding the labelling of an installation containing a flammable substance?

Labelling is not required for hermetically sealed systems

Colour-coding of pipes is sufficient

Labelling is required only in technical rooms

The labelling must indicate the type of substance and the flammability hazard

203 Ťažká

What are the potential consequences of using unsuitable connections in a system containing a flammable substance?

Risk of leakage and the formation of an explosive mixture

Merely installation difficulties

No impact on safety

Merely a reduction in efficiency

204 Ťažká

What is the purpose of installing gas detectors in a room with a refrigeration system?

Early detection of refrigerant leaks and prevention of health risks

Regulating compressor capacity

Measuring the refrigerant temperature

Monitoring pipe pressure

205 Ťažká

How often should gas detection sensors in the service room be checked?

								In accordance with the manufacturer’s instructions and applicable health and safety regulations
							

Before each start-up of the unit

Only after a leak has occurred

Once every 5 years

206 Ťažká

Where should a gas detector be positioned in accordance with EN 378?

Near the control panel

								On the ceiling if the gas is lighter or heavier than air; near the floor if it is lighter or heavier
							

Only at the entrance to the room

Anywhere in the room

207 Ťažká

How should an employee respond when a gas alarm is triggered?

Leave the room immediately and notify their supervisor

Reduce the pressure in the system

Carry on working until they see a leak

Switch off the system and wait for the alarm to stop

208 Ťažká

What safety checks should be carried out when installing a new refrigeration system?

Is the air filter new?

Only the compressor power

								The presence of health and safety signage, adequate ventilation and gas detectors
							

The colour of pipes and hoses

209 Ťažká

Gas detectors should be installed in rooms where:

Any refrigerant is present, regardless of the quantity

Ventilation is natural

The room is less than 5 m²

The amount of refrigerant exceeds a specified permissible threshold

210 Ťažká

What is the minimum number of emergency exits in a plant room (refrigeration plant room) and how should they be signposted?

One exit, clearly marked in the direction of escape

One exit with an information sign about the refrigerant

At least two exits, but signage is optional

Exits do not need to be signposted if the room is small

211 Ťažká

Which measure, when installing a system using a flammable refrigerant, improves its energy efficiency?

No leak test

Thorough leak testing and vacuuming

Increasing the refrigerant charge

Restriction of ventilation

212 Stredne ťažká

What information must appear on the unit’s label?

								Among other things: information stating that the unit contains a fluorinated greenhouse gas, together with the industrial designation of the gas or its chemical name, the mass of the gas and its CO₂ equivalent
							

It does not matter what should be included on the device label.

The manufacturer’s logo and the weight of the unit.

								Markings regarding the weight and capacity of the pipework, together with the colour code and chemical composition of the paints used to coat the frame and casing.
							

213 Ťažká

How do leaks affect systems using flammable refrigerants?

Have no effect

They lower the temperature

They improve efficiency

They cause refrigerant loss, reduced efficiency and a fire hazard

214 Ťažká

Why is it important to limit the amount of refrigerant in HC systems?

It has no effect

It lowers the temperature

It reduces the risk of explosion and improves the system’s operational safety

It increases efficiency

215 Ťažká

Why is the cleanliness of heat exchangers in HC systems important?

Causes leaks

It improves heat transfer and reduces energy consumption

It doesn’t matter

It increases the pressure

216 Ťažká

What maintenance measures improve the efficiency of a system using a flammable refrigerant?

Disabling safety devices

Increasing the refrigerant charge

Lack of servicing

Regular checks for leaks and operating parameters

217 Ťažká

How does the correct selection of components affect a system using a flammable refrigerant?

It lowers the temperature

It increases the amount of refrigerant

It ensures safe and optimal operation and minimises energy losses

It doesn’t matter

218 Ťažká

Why is it important to use the correct service tools in HC systems?

It increases energy consumption

Causes leaks

It ensures operational safety and reduces refrigerant losses

It doesn’t matter

219 Ťažká

How does pipe insulation affect the efficiency of systems containing HC?

It increases the pressure

Causes leaks

It reduces energy losses and improves efficiency

It doesn’t matter

220 Ťažká

Which safety class applies to R744?

A1

A2

A3

B2L

221 Ťažká

In an R744 system operating in supercritical mode, the refrigerant entering the evaporator expansion valve is...

A supercritical fluid

Saturated vapour at intermediate pressure

A subcooled liquid

A two-phase mixture at intermediate pressure

222 Ťažká

In R744 supercritical systems, the gas cooler outlet valve controls:

The gas cooler fans

The outlet temperature of the gas cooler

The pressure in the gas cooler

The inlet temperature to the gas cooler

223 Stredne ťažká

What is the base unit of temperature according to the International System of Units (Système International d’Unités)?

°R

K

°F

°C

224 Stredne ťažká

Which of the following are the most important pieces of information that should be included in the unit’s data sheet:

The owner, installer and service technician of the unit.

Information regarding refrigerant recovery and unit dismantling.

								The make and model of the unit, so that the manufacturer can be contacted to obtain the technical information necessary for servicing.
							

								Operator details, unit details, type and quantity of refrigerant, information regarding servicing and repairs.
							

225 Ťažká

Which statement best describes the behaviour of R717 and mineral compressor oil?

								R717 does not mix with compressor oil, so the oil remains in the system on the high-pressure side as a layer above the R717
							

In an R717 system, a return oil line cannot be used because the oil is too hot

								R717 does not mix with compressor oil, so the oil remains in the system on the low-pressure side as a layer beneath the R717
							

R717 mixes very well with compressor oil and easily returns to the compressor

226 Ťažká

What is the main reason for using K65 copper tubing in some R744 systems?

They come in a wider range of diameters

They have good low-temperature performance

They can withstand higher pressures

They bend easily

227 Ťažká

Which of the following statements is correct regarding the installation of Schrader valves?

								When brazing the valve body to the system, the core must be removed, then refitted and tightened to the correct torque
							

All Schrader valve cores are suitable for all refrigerants

Schrader valves must not be used in R744 systems

Hydrocarbons leak through Schrader valves

228 Ťažká

Which refrigerant can be detected using phenolphthalein paper?

R744

R1234ze

R1270

R717

229 Ťažká

How does a refrigerant shortage affect the high-pressure side of the system (without discharge pressure regulation)?

Discharge pressure will be higher, and the degree of subcooling will be lower

Discharge pressure will be lower, subcooling will be higher

Discharge pressure will be higher, and the degree of subcooling will be higher

The discharge pressure will be lower, and the subcooling will be lower

230 Ťažká

What is the benefit of using helium as a tracer gas in nitrogen during a pressure test?

It has smaller molecules and diffuses more easily

It has a higher pressure than pure nitrogen

It has a distinct odour

It is non-flammable

231 Ťažká

Why should an R744 system that has been drained be initially charged with the refrigerant in gaseous form?

To prevent the drain valve from opening

To prevent damage to the compressor

To prevent the formation of dry ice

To ensure that R744 is charged slowly

232 Ťažká

If an R744 system contains moisture because it has not been properly drained, what is the likely consequence?

Excessively high discharge pressure

								The formation of hydrogen fluoride, which will decompose into hydrofluoric acid and damage the compressor
							

Reduced cooling capacity

The formation of carbonic acid, which will cause damage to the system

233 Ťažká

Which system may require manual oil recovery?

Secondary system using R744

Supercritical ‘booster’ system using R744

An R717 system

R744 cascade system

234 Ťažká

The pressure of R744 at a saturation temperature of 20 °C is approx.

56 bar g

25 bar g

14 bar g

90 bar g

235 Stredne ťažká

Who is responsible for drawing up the equipment or installation record?

There is no such obligation.

The equipment maintenance technician.

The operator of the unit or system.

The person responsible for risk assessment.

236 Ťažká

Which refrigerant is lighter than air?

R744

R1270

R1234ze

R717

237 Ťažká

What hazards are associated with a Class A3 safety agent?

High flammability, lower toxicity

Lower toxicity, does not propagate flames

Slightly flammable, lower toxicity

High toxicity, does not propagate flames

238 Ťažká

18 What is the GWP of R32 (according to AR4)?

3945

0

675

6

239 Ťažká

What factors are taken into account when determining the maximum charge for comfort air-conditioning/heating applications?

Lower flammability limit, height of the indoor unit, floor area

Lower flammability limit, room volume

Practical limit, room volume

Practical limit, height of the indoor unit, floor area

240 Ťažká

What compressor displacement is required for R1270, relative to R404A compressors for the medium-temperature range (cold store)?

600%

Similar

150%

50%

241 Ťažká

At an ambient temperature of 25°C, the standby pressure in the low-pressure stage of an R744 cascade system will typically be…

27.5 bar g

The same as the high-pressure setting on the pressure switch

Higher than the maximum permissible pressure in the low-pressure stage

The same as the pressure set on the relief valve

242 Ťažká

What is the correct definition of critical temperature?

								The temperature at which the vapour pressure of a liquid is equal to the ambient pressure surrounding the liquid
							

The temperature at which, for certain substances, electrical resistance is zero

The temperature at which a substance changes from a gaseous to a solid state

The temperature above which there are no distinct liquid and gaseous phases

243 Ťažká

In a supercritical system, under supercritical conditions, the working fluid in the gas cooler

it loses heat as its temperature drops

it loses heat when its pressure drops

loses heat at constant temperature and pressure

loses heat during a phase change

244 Ťažká

R717 is highly corrosive to

aluminium

copper

titanium

stainless steel

245 Ťažká

What is the effect of repeatedly opening the relief valve?

The valve remains fully open continuously

The relief pressure drops

The relief pressure rises

The valve will not open

246 Stredne ťažká

Oil traps on the suction pipework are required:

before the safety valve.

before the compressor.

always before any rise in the pipeline.

at the inlet to each component of the refrigeration system.

247 Ťažká

What is the relationship between the pressure (P) and temperature (T) of nitrogen at the start (1) and end (2) of the leak test?

P2 = T1/(P1 × T2)

P2 = T2/(P1 × T1)

P2 = (P1 × T2)/T1

P2 = (P1 × T1)/T2

248 Ťažká

What is the recommended alarm level for fixed leak detection systems for R717?

500,000 ppm

500 ppm

50,000 ppm

5,000 ppm

249 Ťažká

Why are compressors with a separate electric motor most commonly used in R717 (NH₃) refrigeration systems?

To increase the amount of refrigerant in the system

								Because NH₃ reacts with the motor windings and hermetic compressors are not used 
							

To reduce the condensing pressure

Because compressors with a separate motor are cheaper

250 Ťažká

Which type of compressor is most commonly used in large ammonia systems?

Rotary vane compressor

Hermetic scroll

Diaphragm compressor

A reciprocating or screw compressor

251 Ťažká

How is the capacity of a piston compressor regulated in NH₃ systems?

By increasing the condensing pressure

By reducing the refrigerant charge

Solely by adjusting the oil volume

By unloading the cylinders or changing the rotational speed

252 Ťažká

How is the capacity of a screw compressor most commonly controlled?

By closing the suction valve

By using a slide valve

By adjusting the oil level

By changing the type of oil

253 Ťažká

When is two-stage compression used in NH₃ systems?

At very low vapour pressures and high pressure differentials

Exclusively in small systems

Only with water-cooled condensers

At small temperature differences

254 Ťažká

What is the advantage of two-stage compression over single-stage compression?

No need for a separator

Lower efficiency

Higher energy consumption

Higher efficiency and lower discharge temperature

255 Ťažká

How does an evaporative condenser used in NH₃ systems work?

Operates without a fan

It utilises the evaporation of water to increase cooling efficiency

It does not require a water supply

It transfers heat only to the air

256 Ťažká

What is the function of the liquid separator in an NH₃ system?

Regulates the condensing pressure

It separates oil from the refrigerant

Increases the discharge temperature

It prevents liquid from entering the compressor

257 Stredne ťažká

When is there a refrigerant leak, even though the compressor is still running?

								When the condensing pressure and suction pressure rise, but there is no superheat.
							

								When the sight glass is full of liquid refrigerant and we observe a rise in the oil level in the compressor sump.
							

								When the suction pressure is low, superheat is high, subcooling is negligible and the temperature difference between the condenser and the expansion valve is small.
							

								When we observe a rise in the refrigerant level in the liquid receiver and the subcooling increases.
							

258 Ťažká

What is the purpose of monitoring the liquid level in the separator?

To increase the oil volume

To reduce the condensing temperature

To control the condenser fan

								To maintain the correct refrigerant level and prevent the compressor from flooding 
							

259 Ťažká

What is the role of the float switch in NH₃ systems?

It monitors the liquid level in the tank or separator

It regulates the condensation temperature

It controls the fan’s operation

It is used to detect leaks

260 Ťažká

What is a thermosiphon in NH₃ systems?

A defrosting device

A type of evaporator

A type of safety valve

An oil circulation system utilising differences in pressure and temperature

261 Ťažká

Why are oils that are immiscible with the refrigerant used in NH₃ systems?

To increase the amount of refrigerant

Because the oil mixes only with water

To reduce the pressure

Because NH₃ does not mix with most compressor oils

262 Ťažká

What is the main function of an oil separator in NH₃ systems?

To separate the oil from the refrigerant and return the oil to the compressor

To increase fan efficiency

Removing moisture from the system

To lower the condensation temperature

263 Ťažká

Which NH₃ system features direct evaporation of the refrigerant in the evaporator?

Glycol system

Direct expansion (DX) system

Thermosiphon system

Indirect system

264 Ťažká

What is the characteristic feature of a flooded evaporator system?

No level control is required

The evaporator is filled exclusively with vapour

No separator is used

The evaporator contains a large amount of liquid, which improves heat transfer

265 Ťažká

What is the main difference between a direct and an indirect system?

In a direct system, there is no evaporator

In an indirect system, NH₃ flows directly into the space being cooled

In an indirect system, no compressor is used

								In an indirect system, NH₃ cools an intermediate medium (e.g. glycol), which in turn cools the load 
							

266 Stredne ťažká

Which components of a refrigeration system can be classified as potential leak points (leaks) subject to regular leak tests?

								Parts of the system located on the high-pressure side (from the compressor up to and including the expansion valve).
							

								Fittings, valves including their stems, seals – including those in replaceable filters and dryers, components exposed to vibration, and connections to measuring, control and safety devices.
							

Hermetic compressors, liquid refrigerant tanks and liquid separators.

								All parts of the refrigeration unit that are connected to the suction side of the refrigeration system.
							

267 Stredne ťažká

What is the test pressure during the pressure leak test of the unit?

								The test pressure for leak testing is equivalent to the maximum operating pressure measured during the operation of the refrigeration unit.  
							

The test pressure (maximum) is 30 bar.

								The test pressure is determined by the person carrying out the leak test based on their experience.
							

								According to the PN-EN 378 standard, at least 0.25 times the maximum permissible pressure for the system (PS).  
							

268 Stredne ťažká

In which part of the refrigeration unit must the recommended leak test be carried out?

								The check should only be carried out at the connection points for measuring instruments (pressure switches, pressure gauges, temperature sensors).
							

								The test must be carried out at all points on the refrigeration unit where there is a potential risk of refrigerant leakage.
							

								The check must be carried out on all parts of the refrigeration system that are connected to the discharge side of the refrigeration circuit.
							

								The test must be carried out on the compressor shut-off valves, solenoid valves and filters.
							

269 Stredne ťažká

When can a given unit be considered perfectly leak-tight?

								A given device can be considered perfectly leak-tight when the pressure drop during the test does not exceed 0.1 bar.
							

								A device can be considered perfectly leak-tight if gas bubbles appear when it is submerged in water.
							

								The device in question is perfectly leak-tight when we have carried out a check using a permanently installed electronic detector.
							

								A given unit can be considered perfectly leak-tight if, during a leak test, the pressure remains constant, taking into account pressure changes caused by temperature variations. Any drop in pressure indicates a leak and requires the location of the leak to be identified.   
							

270 Stredne ťažká

What does EU Regulation 1516/2007 cover?

								The Regulation sets out requirements relating to brazing of refrigeration systems.
							

								The Regulation concerns leak testing of stationary refrigeration, air-conditioning and heat pump equipment containing fluorinated greenhouse gases.  The Regulation sets out the requirements for leak testing of such equipment.
							

								The Regulation addresses the disposal of gases that contribute to the greenhouse effect.
							

The Regulation sets out health and safety requirements for soldering work.

271 Ťažká

Which parts of refrigeration systems must be inspected on a mandatory and regular basis in accordance with EU Regulation 1516/2007?

								Fittings, 2. valves, 3. seals, 4. parts/components exposed to vibration, 5. connections at safety devices.
							

Compressor connections, 2. connections on the liquid refrigerant tank

Only compressor connections, as these are subject to vibration.

								Connections on the condenser, as there is high pressure and the refrigerant is in liquid form
							

272 Ľahká

What is superheat?

It is the amount of heat required to increase the pressure.

								It is the amount of heat required to cause the vapour formed from a liquid to become superheated.
							

It is the amount of heat required to heat a liquid.

It is the amount of heat required to turn a liquid into vapour.

273 Ťažká

In accordance with EU Regulation 1516/2007, there are several methods of leak testing. What are these methods called?

								We distinguish between quality control methods for supplied materials and electronic testing methods.
							

We distinguish between physical and chemical methods.

We distinguish between direct and indirect methods of leak detection.

								We distinguish between methods for quality control of supplied materials and leak testing methods that do not involve quality control of supplied materials.
							

274 Ťažká

In accordance with EU Regulation 1516/2007, to whom can we entrust the responsibilities for leak testing of refrigeration systems?

								The check may only be carried out by a person who has previously carried out such a check.
							

The check may be carried out by a specialist in leak testing.

								The test may only be carried out by a competent person with the relevant skills, who holds a certificate attesting to the necessary knowledge in this field. They must also hold a certificate for companies regarding the operation and maintenance of refrigeration equipment charged with F-gases.
							

								The inspection may be carried out by a person employed and appointed by the owner of the installation.
							

275 Ťažká

In accordance with EU Regulation 1516/2007, what conditions must be met in order to carry out a leak test on refrigeration systems using ultraviolet (UV) light?

								A prerequisite for carrying out a leak test using UV is that such a test is technically feasible.
							

								A prerequisite for carrying out a leak test using UV is having the appropriate technical resources, the relevant materials supplied, and suitable safety goggles.
							

								A prerequisite for carrying out the inspection is holding the relevant authorisation for pressure testing issued by the UDT.
							

								The manufacturer of the refrigeration equipment must confirm that the aforementioned UV method can be used. A UV leak test may be carried out by a qualified person who holds the relevant qualifications (certificate).   
							

276 Ťažká

In accordance with EU Regulation 1516/2007, which leak testing methods are classified as direct leak testing methods?

								Leak test following the creation of a vacuum and leak detection using a foaming solution.
							

								Detection of leaks using a handheld leak detector and/or a fixed leak detection system; 2. Detection of leaks using a special dye with UV-fluorescent properties; 3. Detection of leaks using a foaming solution.
							

								Leak test using nitrogen with a tracer gas, an electronic detector and pressure measurement.
							

								Leak testing by measuring pressure changes and the method of submerging the device/system in water.
							

277 Ťažká

In accordance with EU Regulation 1516/2007, which methods are classified as indirect leak testing methods?

This method is based on electronic leak detection.

Leak detection using a UV tracer.

								This method is based on the analysis of the following parameters: pressure, temperature, operating pressure, liquid level, oil leakage, etc.
							

								It utilises pressure and temperature measurements, as well as an ultrasonic method.
							

278 Stredne ťažká

How should the pressure be increased during a pressure leak test?

We increase the pressure as quickly as possible.

We increase the pressure in any way.

We increase the pressure at a rate of 10 bar/s.

								We increase the pressure gradually whilst checking for leaks, until the test pressure is reached, at a rate of no more than 2 bar/min
							

279 Stredne ťažká

What electronic equipment should be used to carry out leak testing?

Only with devices fitted with an ‘Ion Pump’ sensor.

Only with devices fitted with an infrared detector.

Only with devices fitted with hot cathodes.

Only using devices with verified measurement sensitivity.

280 Stredne ťažká

What documentation should be checked before starting a leak test?

Check the operating instructions for the machine/equipment.

Check the time sheets of the staff responsible for the machinery/equipment.

								The maintenance log and the machine/device operating instructions must be checked.
							

Check the stock ledger (accounts).

281 Stredne ťažká

What information must be recorded when drawing up the leak test report?

								The number of locations where leaks have occurred and the date of the inspection.
							

								The method used to carry out the leak test, the number of faults, the method of repairing the faults, the time taken to work on the installation, and the cost of the repair.
							

								The date of the inspection, the number of faults (leaks), the location of the faults (leaks), the proposed method of rectifying the fault/defect (leak), attached documents and a signature.
							

								The date of the inspection, a record of the occurrence of the leak, and a signature.
							

282 Stredne ťažká

What pressure values should be used for the pressure leak test?

At the discretion of the person authorised to carry out the pressure test.

The pressure value for the leak test is 10–12 bar.

The pressure for the leak test is 2–3 bar.

								Use a pressure not exceeding the maximum permissible pressure for the system (PS).
							

283 Stredne ťažká

What is temperature slip?

								A specific temperature cannot be assigned to a given vapour pressure. There is a temperature difference between the start and end of evaporation.
							

It involves an increase in temperature.

A specific temperature corresponds to a given vapour pressure.

It involves a decrease in temperature.

284 Ťažká

What does a vacuum leak test involve?

								With the vacuum pump running continuously, we are able to maintain the required vacuum level in the system.
							

								After switching off the vacuum pump, we check whether the pressure in the system rises
							

								With the vacuum pump switched on, check whether the pressure in the system rises as a result of a leak.
							

								If the pressure in the refrigeration system were to rise, we switch on the vacuum pump as required.
							

285 Ťažká

How often should leak tests be carried out on equipment containing 1.5 kg of R404A refrigerant (5.9 tonnes of CO₂ equivalent)?

At least once every 12 months.

On initial commissioning.

Once every six months.

Only when servicing the unit.

286 Ťažká

How often should leak tests be carried out on equipment containing 7 kg of R404A refrigerant (27.45 tonnes of CO₂ equivalent)?

At least once every 12 months.

Only when servicing the unit.

Once every six months.

On initial commissioning.

287 Stredne ťažká

In which appliances and systems is the installation of a permanent leak detection system required?

								In equipment and installations containing at least 30 kg of fluorinated greenhouse gases.
							

In equipment and systems containing at least 500 tonnes of CO₂ equivalent.

In equipment and systems containing at least 5 tonnes of CO₂ equivalent.

In equipment and systems containing at least 50 tonnes of CO₂ equivalent.

288 Ťažká

In accordance with Regulation (EU) 2024/573 of the European Parliament and of the Council, a fixed leak detection system is required when:

								The installation of a fixed leak detection system is optional, but it helps to reduce the number of leak checks required on the equipment each year.
							

								The refrigerant charge of the refrigeration equipment is at least 100 kg of ODS.
							

								The charge of an F-gas refrigerant in a refrigeration unit is at least 500 tonnes of CO₂ equivalent.
							

The refrigeration equipment is operated in an enclosed space.

289 Ťažká

Under Regulation (EC) No 1516/2007 and the F-gas Act, which leak detection methods may not be carried out by a person holding a Category E certificate?

Leak detection using a foaming solution.

Leak testing using a fluorescent dye.

Measuring leaks using a handheld leak detector.

Visual leak inspection.

290 Ťažká

According to the current regulation, what sensitivity must a handheld leak detector have?

8 g/year.

5 g/year.

10 g/year.

3 g/year.

291 Stredne ťažká

Which category of F-gas certificate (A1, A2, B, C, D, E) authorises the performance of leak tests on refrigeration equipment:

All except category D.

Categories D and E.

Only categories A1 and A2.

Category E only.

292 Ťažká

Within what timeframe must a leak test be carried out on a stationary refrigeration system after a leak has been repaired, in accordance with EU Regulation 2024/573 on F-gases?

At the next periodic inspection.

Immediately after the repair.

At any time.

Between 24 hours and 1 month after the repair.

293 Ťažká

At what intervals should leak tests be carried out on refrigeration equipment containing more than 500 tonnes of CO₂ equivalent of fluorinated greenhouse gases that does not have a leak detection system installed?

Once a month.

Once every 6 months.

Once every 3 months.

Once every 12 months.

294 Stredne ťažká

Why is it advisable to subcool the liquid refrigerant?

								This is advisable because it allows a smaller evaporator to be used (lower refrigerant temperature at the evaporator inlet).
							

								This is advisable because it allows a smaller expansion valve to be used (less superheat at the valve).
							

								This is advisable because it allows a smaller condenser to be used (smaller heat exchange surface area).
							

								This is advisable because it ensures that the liquid refrigerant, free of vapour bubbles, enters the expansion valve.
							

295 Stredne ťažká

What should be done following repairs to a leak in the refrigeration unit of a refrigerated trailer?

A visual inspection should be carried out only on bolted and soldered joints.

								You must enter the details into the equipment log (including the quantities of refrigerant recovered and used) and inform the Operator that an additional leak test must be carried out by a certified person within one month of the repair.
							

								The unit must be charged with an alternative refrigerant, started up, and the refrigerant parameters checked at the service valve located on the liquid receiver.
							

An invoice for the service work carried out must be issued as soon as possible.

296 Stredne ťažká

Recovery of fluorinated greenhouse gases means:

								The reuse of fluorinated greenhouse gases following a basic purification process.
							

								The collection and storage of fluorinated greenhouse gases originating, for example, from machinery, equipment and containers.
							

								The reprocessing of fluorinated greenhouse gases to achieve their specified standard properties.
							

								The final decommissioning and withdrawal from service or use of a product or piece of equipment containing fluorinated greenhouse gases.
							

297 Stredne ťažká

Who is authorised to recover refrigerant from stationary refrigeration equipment:

The administrator of the operator’s account.

The operator.

The owner of the installation.

A service technician holding an F-gas certificate in the relevant category.

298 Stredne ťažká

Recovered refrigerants must be stored:

In a cylinder that previously contained the same type of refrigerant.

In any used refrigerant cylinder.

In a specially adapted and labelled cylinder fitted with a two-way valve.

In any pressure vessel that has been officially certified.

299 Stredne ťažká

When should the recovery of fluorinated greenhouse gases be carried out:

Always during servicing and maintenance of equipment.

Only prior to the final disposal of equipment.

								Before the final disposal of equipment and, where applicable, during its servicing and maintenance.
							

Before each leak test of the equipment.

300 Stredne ťažká

What should be done if the refrigerant recovered from the system is contaminated, e.g. with acid, air or moisture?

Purify the mixture by passing it through a particulate filter and reuse it.

You should attempt to purify the mixture yourself using a dehydrating filter.

Add a special contaminant neutraliser to the mixture.

								Such a mixture must be handed over to a specialist authorised company for regeneration or disposal.
							

301 Stredne ťažká

What should be done if different types of refrigerants become mixed in a storage cylinder (container)?

The mixture should be purified by passing it through a filter-drain and reused.

Send this mixture to a specialist authorised company to have it neutralised.

Add a special refrigerant to the mixture.

You should attempt to separate the mixture into its individual components.

302 Stredne ťažká

How does refrigerant recovery using the Push-Pull method work?

								It involves using a recovery unit to draw (pull) the refrigerant vapour from the cylinder and then force it (push) into the low-pressure side of the system.
							

								This involves using a suction device (compressor) to ensure that the refrigerant, in liquid form, is transferred into the cylinder. 
							

								This involves the refrigerant being alternately drawn from the suction side and then from the discharge side of the refrigeration unit (compressor).
							

								This involves injecting nitrogen from the cylinder into the unit and expelling the liquid refrigerant from the unit.
							

303 Stredne ťažká

What are the methods for managing waste refrigerant?

Disposal, storage.

Recovery, disposal.

Regeneration, recovery.

Recycling, regeneration, disposal.

304 Stredne ťažká

The most advantageous method of managing waste refrigerant is:

Regeneration.

Storage.

Recycling.

Disposal.

305 Stredne ťažká

The lower the evaporation temperature, ...

								...the lower the density of the refrigerant and the lower the mass of the flowing refrigerant.
							

								...the greater the density of the refrigerant and the mass flow rate of the flowing refrigerant. 
							

								…the greater the density of the refrigerant and the lower the mass flow rate of the refrigerant.
							

								...the lower the refrigerant density, and the greater the cooling capacity of the compressor.
							

306 Stredne ťažká

How should pressure vessels (e.g. refrigerant cylinders) be marked?

They should bear only markings relating to weight and capacity.

It is irrelevant how pressure vessels should be marked.

								They should bear, amongst other things, information such as: the number of the standard applied to their design, construction and testing; the identification marks of the country of approval and the inspection body; the date of the acceptance test; and the manufacturer’s and operational marks.
							

They should bear the manufacturer’s logo and the date of manufacture.

307 Stredne ťažká

The recovery of refrigerants does not require the use of:

A refrigerant recovery station.

								Scales with a measurement range suitable for the size of the cylinder being filled.
							

Hoses with shut-off valves.

An electronic leak detector.

308 Stredne ťažká

What functions does the compressor perform in a refrigeration system?

The compressor creates a vacuum on the suction side of the system

The compressor condenses the refrigerant.

								The compressor compresses ambient air and increases the pressure of the refrigerant.
							

								The compressor draws in refrigerant vapour from the evaporator, compresses it, and then forces it into the condenser, raising the pressure to the required condensing pressure.
							

309 Ľahká

What is the compressor’s compression ratio?

								It is the ratio of the discharge pressure to the effective capacity of the compressor (p/Vk).
							

								It is the ratio of the suction pressure to the discharge pressure of the compressor (po/pk).
							

								It is the amount of refrigerant that will be compressed in a single compressor cycle relative to the heat capacity.
							

								It is the ratio of the discharge pressure to the suction pressure of the compressor (pk/po).
							

310 Stredne ťažká

What is compressor flooding?

Flooding the compression chamber with liquid refrigerant or oil.

Flooding of the compressor due to rainfall.

Suction of liquid refrigerant into the compressor’s suction line.

A large amount of liquid refrigerant in the evaporator.

311 Stredne ťažká

To what extent do we regulate the compressor motor’s rotational speed when using a frequency converter?

From approximately 30% to 90% of capacity.

								Regulating the compressor motor speed is not the same as regulating the cooling capacity.
							

Up to a maximum of 10 per cent.

								Approximately from 30 to 75 Hz, which corresponds to around 60% to 150% of the cooling capacity.
							

312 Ľahká

What is the theoretical displacement of a compressor?

								This is the volume of refrigerant that flows through a reciprocating compressor during a single piston cycle.
							

								It is the volume of refrigerant delivered by a reciprocating compressor per unit of time, usually referred to by the manufacturer as the displacement. It depends on the compressor’s geometric dimensions and rotational speed.
							

								The displacement capacity of a compressor is expressed by the coefficient of performance (COP) 
							

								The displacement of a compressor is determined by the dimensions of the cylinder – its volume (cm³)
							

313 Stredne ťažká

Why is it essential to observe the correct phase sequence for scroll compressors and screw compressors?

Because these types of compressors are sensitive to voltage drops.

								Because changing the phase sequence would reverse the direction of rotation of the compressor rotors, which could result in damage to the compressors.
							

								Because this type of compressor has difficulty starting up if the phase sequence is changed.
							

								Because the motor speed would decrease, and consequently the compressor’s capacity.
							

314 Stredne ťažká

The cycle of a two-stage vapour-compression refrigeration system should have, in each stage of the system:

a compression ratio of less than 6

a compression ratio of less than 18.

a compression ratio greater than 8.

a compression ratio of less than 8.

315 Stredne ťažká

Why is it necessary to seal the shafts in gland-sealed refrigeration compressors?

Because it prevents oil leakage.

								Because we need to prevent air from entering the compressor and we need to prevent refrigerant from leaking from the compressor.
							

Because it ensures the bearing remains lubricated.

Because it protects the compressor’s crankshaft bearing.

316 Stredne ťažká

When is the refrigerant sufficiently cooled?

When no vapour bubbles are observed forming in the liquid sight glass.

When the outlet from the condenser is cold.

When the liquid distributors are warm.

When the evaporator is covered in frost.

317 Stredne ťažká

Why should the compressor crankcase be heated?

Heating prevents the refrigerant from dissolving in the oil.

Heating keeps the lubricating oil in a liquid state.

Heating ensures that the lubricating oil is de-watered.

								Heating improves the dissolution of the refrigerant in the oil, which is beneficial for its viscosity.
							

318 Ľahká

What is the dead volume of a compressor?

This is the space between the bottom of the piston and the crankshaft cover.

It is the space between the valve plate and the top of the piston.

This is the space between the side surface of the piston and the cylinder.

								It is the space between the valve plate and the bottom dead centre of the piston.
							

319 Stredne ťažká

What are compressor sets?

								These consist of a larger number (several) of compressors connected in parallel and mounted on a common frame.
							

These are multiple (several) air-cooled condensers.

These are sets comprising several compressors connected in any configuration.

These are units consisting of two-stage compressors.

320 Stredne ťažká

What are the advantages of compressor units?

Easy modification of the system.

These are inexpensive and easy-to-install units.

Space-saving and lower energy consumption.

The ability to adjust the cooling capacity as required.

321 Stredne ťažká

What do we mean by the ‘application range’ of a compressor?

								By this term, we mean the following parameters: the evaporation and condensation temperatures (to and tk), or the pressure values that determine the compressor’s application.
							

								By this term, we mean that the compressor’s application range is determined by the evaporation temperature ‘to’ at a given ambient temperature.  
							

								By this term, we mean that the compressor’s operating range is determined by the evaporation temperature ‘to’ during operation. 
							

								By this term, we mean the following parameters: compressor capacity, type of refrigerant, and the compressor’s geometric dimensions.
							

322 Stredne ťažká

What are the basic functions of oil in a compressor?

The oil seals the gap between the piston and the cylinder.

The oil absorbs moisture from the refrigerant that enters the compressor.

The oil seals any leaks that develop in the system.

								The oil lubricates both the bearings and the sliding surfaces of the compressor components, and cools the compressor by transferring the heat generated during compression to the compressor’s outer casing.
							

323 Stredne ťažká

What are the most effective ways of regulating the compressor’s cooling capacity?

By partially covering the evaporator to reduce the heat exchange surface area.

Using an expansion valve.

By means of pressure control valves.

								By changing the compressor’s displacement, by varying the rotational speed, or by deactivating individual cylinders. 
							

324 Stredne ťažká

What does compressor bypass control involve?

The bypass control is not used to regulate the compressor.

								High-pressure liquid refrigerant is injected on the suction side of the compressor.
							

								Refrigerant in the form of cooled, high-pressure vapour is introduced into the suction line.   
							

								Hot, high-pressure refrigerant vapour is drawn in on the suction side of the compressor.
							

325 Stredne ťažká

What is the fundamental difference between hermetic and semi-hermetic compressors?

								Semi-hermetic compressors are characterised by the quiet operation of the entire unit.
							

								The casing of semi-hermetic compressors can be dismantled, whereas the casing of hermetic compressors cannot be dismantled.
							

								The housing of a hermetic compressor and the compressor itself form a single unit.
							

								 Both types of compressors are disassemblable, and the difference lies in their varying capacities.
							

326 Stredne ťažká

How does a scroll compressor work?

A scroll compressor is also known as a turbo compressor.

								It is a device fitted with two spirals. It is a type of positive displacement (volumetric) compressor in which compression takes place through the interaction of the two spirals.  
							

It uses two screws to compress the refrigerant.

It is a type of piston-type device.

327 Stredne ťažká

What physical process takes place in the evaporator?

It cools the refrigerant flowing through it.

It causes the refrigerant flowing through it to condense.

The liquid refrigerant evaporates and a small amount of it becomes superheated.

								The medium flowing through the evaporator (glycol, water) evaporates, whilst the refrigerant condenses.
							

328 Stredne ťažká

What is the purpose of regulating the compressor’s capacity?

It allows the cooling capacity to be adjusted to meet requirements.

								It ensures that the cooling capacity is adjusted based on condensing temperatures.
							

Capacity control protects the compressor from low thermal loads.

It ensures adequate lubrication of the compressor.

329 Stredne ťažká

Why is inverter speed control suitable for refrigeration compressors?

								Inverter speed control reduces energy consumption only under natural conditions.
							

								Inverter speed control can be used with any type of compressor to ensure adequate lubrication.
							

								By reducing the speed of the refrigeration compressor motor, inverter speed control improves the return oil flow to the compressor.
							

								Inverter speed control enables continuous, smooth regulation of cooling capacity.
							

330 Stredne ťažká

Does the suction gas temperature affect the cooling capacity of the compressor?

It does, but only for reciprocating compressors.

It does, but only if the gas is deeply cooled.

Temperature has no effect on the compressor’s cooling capacity.

It has a significant effect on performance.

331 Stredne ťažká

In the case of compressor units fitted with an oil level control system, is it necessary to install the compressors at the same height?

Yes.

Only scroll compressors.

Only screw compressors.

No.

332 Stredne ťažká

What functions does a compressor powered by the vehicle’s engine perform in a transport refrigeration system?

This compressor condenses the refrigerant whilst the vehicle is in motion.

								The compressor compresses ambient air and increases the pressure of the refrigerant.
							

								This compressor draws in refrigerant vapour from the evaporator, compresses it and then forces it into the condenser whilst the vehicle’s engine is running.
							

								This compressor creates a vacuum on the suction side of the system whilst the vehicle’s engine is switched off.
							

333 Stredne ťažká

Which natural fluids absorb heat from the refrigerant in the condenser?

Water and an antifreeze mixture.

Water or air.

Air and CO2.

Ammonia

334 Stredne ťažká

What is the function of the condenser in refrigeration systems?

								The heat absorbed in the evaporator and transferred during the compression process is then released into the environment via the condenser.
							

Heat released in the regenerative heat exchanger is absorbed by the condenser.

								Heat from the compressor is then released into the environment via the condenser.
							

								The heat absorbed in the evaporator is then released into the environment via the condenser
							

335 Stredne ťažká

If the condensation temperature is higher than the critical point temperature of the refrigerant, condensation:

will always occur regardless of the temperature.

temperature has no effect on condensation.

will occur provided a specially designed condenser is used.

will not occur.

336 Stredne ťažká

How does the subcooling of the refrigerant take place within a refrigeration system?

Subcooling using an additional heat exchanger and liquid nitrogen.

Subcooling of the liquid refrigerant in the final section of the condenser.

Subcooling using high-pressure hot vapour.

Subcooling of the refrigerant using oil (dissolving the refrigerant in oil).

337 Stredne ťažká

What is the purpose of controlling the condenser fan speed?

								Condenser fan speed control ensures that the condensing pressure is maintained at the correct level.
							

								Condenser fan speed control safeguards against the maximum permissible condensing pressure.
							

Condenser fan speed control reduces energy efficiency.

Dispersion of the refrigerant in the event of a system leak.

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