1

Ťažká

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


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

2

Ťažká

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


Dust and moisture may enter
There is a risk of refrigerant leakage
It is a potential source of ignition
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?


3 m
2 m
0.5 m
1 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?


20 kg
18 kg
33 kg
9 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?


1.0 kg
2.5 kg
1.5 kg
10 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
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

7

Ťažká

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


A fire extinguisher
Thick gloves
Tinted safety goggles
Fire blanket

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, 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
Recover the R32 until a vacuum is achieved
Vent the R32 to the outside and drain the system

9

Stredne ťažká

What is R1270?


Butane
Propene
Propene
Isobutane

10

Ťažká

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


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

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 connection sizes
Different low-pressure switch setting
A flammable refrigerant recovery unit has no ignition sources

12

Ťažká

Which of the following is a source of ignition?


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

13

Ťažká

What substance is produced when R32 is burnt?


Carbon monoxide
Hydrogen fluoride
Phosgene
Hydrochloric acid

14

Ťažká

What type of refrigerant is R1234ze?


Chloro-fluoro-hydrocarbon
Hydrochlorofluoro-hydrocarbon
Hydrocarbon
Hydrofluoroolefin

15

Ťažká

What hazards does a Group A3 refrigerant pose?


High toxicity, high flammability
Low toxicity, moderate flammability
Low toxicity, highly flammable
High 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
4.93 kg
1.0 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?


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

19

Ťažká

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


Because it affects the charge weight
Because it affects the charging rate
Because it increases operating pressures
Because it affects energy efficiency

20

Ťažká

What is the GWP value for R290?


3
7
675
A. 0.02

21

Ťažká

Which of the following is not a source of ignition?


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

22

Ťažká

What is R290?


Propylene
Propene
Butane
Propene

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?


1.5 kg
2.5 kg
150 g
1.0 kg

24

Ťažká

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


A relay is never required for compressors using flammable refrigerants
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
It could be a source of ignition

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?


1 m
10 m
5 m
3 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?


20 kg
8 kg
17 kg
3.6 kg

27

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
Fit a long hose to the pump outlet to remove HC away from the system
Position the vacuum pump 3 metres above floor level

28

Ťažká

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


A fire extinguisher
Fire blanket
Tinted safety goggles
Thick gloves

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?


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

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?


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
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

31

Ťažká

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


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

32

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
The oil in the recovery unit is not soluble in R600a
It contains ignition sources
The recovery unit cannot withstand the working pressure of 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)?


2.27 kg
6.18 kg
227 kg
618 kg

34

Ťažká

What type of refrigerant is R32?


Hydrofluoroolefin
Hydrocarbon
Hydrofluorocarbon
Carbon dioxide

35

Ťažká

What hazards do A2L refrigerants pose?


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

36

Ťažká

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


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


Twice
Seven times
Half
The same

38

Ťažká

What is the GWP value for R32?


675
7
3
0

39

Ťažká

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


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

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

41

Ťažká

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


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

42

Ťažká

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


It has no significant impact on safety
It may lead to the use of tools that are a source of ignition
It may lead to the incorrect selection of oil
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
Cylinder colour and date of manufacture
Name of the substance, hazard pictogram, UN number
Gross weight and batch number

44

Ťažká

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


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

45

Ťažká

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


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

46

Ťažká

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


Measuring the refrigerant temperature
Regulating compressor capacity
Early detection of refrigerant leaks and prevention of health risks
Monitoring pipe pressure

47

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
Once every 5 years
Before each start-up of the unit
Only after a leak has occurred

48

Ťažká

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


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
Near the control panel

49

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
Switch off the system and wait for the alarm to stop
Carry on working until they see a leak

50

Ťažká

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


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

51

Ťažká

Gas detectors should be installed in rooms where:


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

52

Ťažká

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


One exit with an information sign about the refrigerant
Exits do not need to be signposted if the room is small
One exit, clearly marked in the direction of escape
At least two exits, but signage is optional

53

Ťažká

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


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

54

Ťažká

How do leaks affect systems using flammable refrigerants?


They improve efficiency
They lower the temperature
They cause refrigerant loss, reduced efficiency and a fire hazard
Have no effect

55

Ťažká

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


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

56

Ťažká

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


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

57

Ťažká

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


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

58

Ťažká

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


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

59

Ťažká

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


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

60

Ťažká

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


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

61

Ťažká

What hazards are associated with a Class A3 safety agent?


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

62

Ťažká

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


0
6
675
3945

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

64

Ťažká

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


50%
600%
150%
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