1

Ťažká

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


Flammable gas detector
Fire blanket
High-visibility jacket
Tinted safety goggles

2

Ťažká

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


It is a potential source of ignition
Dust and moisture may enter
There is a risk of refrigerant leakage
The pressure switch setting will not be correct

3

Ťažká

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


1 m
3 m
0.5 m
2 m

4

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
18 kg
20 kg
33 kg

5

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?


2.5 kg
10 kg
1.0 kg
1.5 kg

6

Ťažká

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


Fit a long hose to the pump outlet to remove HC away from the system
Use an ATEX-certified vacuum pump in a well-ventilated area
There is no need to evacuate such systems
Position the vacuum pump 3 metres above floor level

7

Ťažká

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


Tinted safety goggles
A fire extinguisher
Fire blanket
Thick gloves

8

Ťažká

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


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

9

Stredne ťažká

What is R1270?


Propene
Butane
Isobutane
Propene

10

Ťažká

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


Leak detection foam
Electronic HFC leak detector
Soapy water solution
Electronic leak detector for flammable refrigerants

11

Ťažká

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


A different colour for the station
Different low-pressure switch setting
Different connection sizes
A flammable refrigerant recovery unit has no ignition sources

12

Ťažká

Which of the following is a source of ignition?


‘n’ type thermostat
Ex-certified evaporator fan motor
Contactor
Defrost heating element

13

Ťažká

What substance is produced when R32 is burnt?


Hydrogen fluoride
Phosgene
Hydrochloric acid
Carbon monoxide

14

Ťažká

What type of refrigerant is R1234ze?


Hydrofluoroolefin
Hydrocarbon
Hydrochlorofluoro-hydrocarbon
Chloro-fluoro-hydrocarbon

15

Ťažká

What hazards does a Group A3 refrigerant pose?


High toxicity, moderate flammability
High toxicity, high flammability
Low toxicity, highly flammable
Low toxicity, moderate flammability

16

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)?


0.285 kg
1.0 kg
4.93 kg
1.5 kg

17

Ťažká

What is the cooling capacity of R32 compared to R410A?


105%
60%
130%
75%

18

Ťažká

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


To avoid a source of ignition in the event of a flammable refrigerant leak
Because they are more reliable
Because they are more energy-efficient
Because they must be kept running continuously to disperse the leaking refrigerant

19

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

20

Ťažká

What is the GWP value for R290?


A. 0.02
675
3
7

21

Ťažká

Which of the following is not a source of ignition?


Electrical switch
An Ex-certified fan motor
Light switch
Open mechanical pressure switch

22

Ťažká

What is R290?


Propene
Butane
Propene
Propylene

23

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?


2.5 kg
150 g
1.5 kg
1.0 kg

24

Ťažká

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


The method of starting the compressor motor differs from that used with HFCs
Current consumption differs for compressors using flammable refrigerants compared to those using HFCs
It could be a source of ignition
A relay is never required for compressors using flammable refrigerants

25

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
10 m
5 m

26

Ťažká

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


8 kg
3.6 kg
20 kg
17 kg

27

Ťažká

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


Use an ATEX-certified vacuum pump in a well-ventilated area
There is no need to evacuate systems containing R290
Position the vacuum pump 3 metres above floor level
Fit a long hose to the pump outlet to remove HC away from the system

28

Ťažká

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


Thick gloves
Fire blanket
A fire extinguisher
Tinted safety goggles

29

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?


Ensure the area is well ventilated and use a flammable gas detector to check the area
You must not desolder joints on a system containing a flammable refrigerant; they must be cut using a pipe cutter
Work outdoors
Purge the system with oxygen-free nitrogen

30

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?


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

31

Ťažká

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


Electronic leak detector for flammable refrigerants
Fluorescent dye and a UV lamp
Electronic HFC leak detector
Leak detection foam

32

Ťažká

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


The recovery unit cannot withstand the working pressure of R600a
It contains ignition sources
The low-pressure switch setting will not be suitable for R600a due to its lower operating pressure
The oil in the recovery unit is not soluble in R600a

33

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
618 kg
2.27 kg
6.18 kg

34

Ťažká

What type of refrigerant is R32?


Hydrofluoroolefin
Hydrofluorocarbon
Carbon dioxide
Hydrocarbon

35

Ťažká

What hazards do A2L refrigerants pose?


High toxicity, moderate flammability
High toxicity, high flammability
Low toxicity, moderate flammability
Low toxicity, high flammability

36

Ťažká

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


Nitrous oxide is produced
Hydrogen fluoride is produced
Citric acid is produced
Phosgene is produced

37

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?


The same
Seven times
Half
Twice

38

Ťažká

What is the GWP value for R32?


0
675
3
7

39

Ťažká

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


Because R290 is only used in systems with a charge of less than 150g
Because these systems never have liquid receivers
Due to lower operating pressures
The charge mass is significantly lower than in an HFC system, as the density is much lower

40

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 dilute the refrigerant in the event of a leak
To ensure that the discharge pressure never becomes excessive

41

Ťažká

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


The name of the refrigerant, the hazard symbol and basic safety information
Agent name only
Information about the cylinder owner
Net weight only

42

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

43

Ťažká

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


Manufacturer’s name and country of origin
Name of the substance, hazard pictogram, UN number
Cylinder colour and date of manufacture
Gross weight and batch number

44

Ťažká

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


Labelling is required only in technical rooms
Labelling is not required for hermetically sealed systems
Colour-coding of pipes is sufficient
The labelling must indicate the type of substance and the flammability hazard

45

Ťažká

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


Merely a reduction in efficiency
No impact on safety
Risk of leakage and the formation of an explosive mixture
Merely installation difficulties

46

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
Measuring the refrigerant temperature
Monitoring pipe pressure
Regulating compressor capacity

47

Ťažká

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


Before each start-up of the unit
In accordance with the manufacturer’s instructions and applicable health and safety regulations
Once every 5 years
Only after a leak has occurred

48

Ťažká

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


Near the control panel
Anywhere in the room
Only at the entrance to the room
On the ceiling if the gas is lighter or heavier than air; near the floor if it is lighter or heavier

49

Ťažká

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


Leave the room immediately and notify their supervisor
Switch off the system and wait for the alarm to stop
Carry on working until they see a leak
Reduce the pressure in the system

50

Ťažká

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


The colour of pipes and hoses
Only the compressor power
The presence of health and safety signage, adequate ventilation and gas detectors
Is the air filter new?

51

Ťažká

Gas detectors should be installed in rooms where:


Any refrigerant is present, regardless of the quantity
The amount of refrigerant exceeds a specified permissible threshold
Ventilation is natural
The room is less than 5 m²

52

Ťažká

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


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

53

Ťažká

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


Restriction of ventilation
Increasing the refrigerant charge
No leak test
Thorough leak testing and vacuuming

54

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

55

Ťažká

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


It increases efficiency
It has no effect
It reduces the risk of explosion and improves the system’s operational safety
It lowers the temperature

56

Ťažká

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


It improves heat transfer and reduces energy consumption
It doesn’t matter
It increases the pressure
Causes leaks

57

Ťažká

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


Lack of servicing
Disabling safety devices
Increasing the refrigerant charge
Regular checks for leaks and operating parameters

58

Ťažká

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


It ensures safe and optimal operation and minimises energy losses
It doesn’t matter
It increases the amount of refrigerant
It lowers the temperature

59

Ťažká

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


It increases energy consumption
It ensures operational safety and reduces refrigerant losses
Causes leaks
It doesn’t matter

60

Ťažká

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


Causes leaks
It reduces energy losses and improves efficiency
It doesn’t matter
It increases the pressure

61

Ťažká

What hazards are associated with a Class A3 safety agent?


High toxicity, does not propagate flames
Lower toxicity, does not propagate flames
High flammability, lower toxicity
Slightly flammable, lower toxicity

62

Ťažká

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


675
3945
0
6

63

Ťažká

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


Practical limit, height of the indoor unit, floor area
Lower flammability limit, room volume
Practical limit, room volume
Lower flammability limit, height of the indoor unit, floor area

64

Ťažká

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


Similar
150%
50%
600%