1

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

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
It is a potential source of ignition
The pressure switch setting will not be correct
There is a risk of refrigerant leakage

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
2 m
0.5 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?


18 kg
33 kg
20 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?


2.5 kg
1.0 kg
10 kg
1.5 kg

6

Ťažká

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


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

7

Ťažká

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


A fire extinguisher
Fire blanket
Tinted safety goggles
Thick gloves

8

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 and drain the system
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

9

Stredne ťažká

What is R1270?


Isobutane
Butane
Propylen
Propene

10

Ťažká

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


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

11

Ťažká

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


Different connection sizes
A different colour for the station
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?


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

13

Ťažká

What substance is produced when R32 is burnt?


Phosgene
Hydrochloric acid
Carbon monoxide
Hydrogen fluoride

14

Ťažká

What type of refrigerant is R1234ze?


Hydrocarbon
Hydrofluoroolefin
Chloro-fluoro-hydrocarbon
Hydrochlorofluoro-hydrocarbon

15

Ťažká

What hazards does a Group A3 refrigerant pose?


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


4.93 kg
0.285 kg
1.5 kg
1.0 kg

17

Ťažká

What is the cooling capacity of R32 compared to R410A?


60%
130%
105%
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 increases operating pressures
Because it affects the charging rate
Because it affects energy efficiency
Because it affects the charge weight

20

Ťažká

What is the GWP value for R290?


A. 0.02
675
7
3

21

Ťažká

Which of the following is not a source of ignition?


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

22

Ťažká

What is R290?


Propylene
Butane
Propene
Ethane

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
1.5 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
It could be a source of ignition
The method of starting the compressor motor differs from that used with HFCs

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?


10 m
3 m
1 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?


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?


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 systems containing R290
Use an ATEX-certified vacuum pump in a well-ventilated area

28

Ťažká

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


Tinted safety goggles
Thick gloves
Fire blanket
A fire extinguisher

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?


Purge the system with oxygen-free nitrogen
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

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
Recover the R1270 until a vacuum is achieved
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 and drain the system

31

Ťažká

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


Electronic HFC leak detector
Electronic leak detector for flammable refrigerants
Fluorescent dye and a UV lamp
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
The oil in the recovery unit is not soluble in R600a
It contains ignition sources
The low-pressure switch setting will not be suitable for R600a due to its lower operating pressure

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)?


618 kg
227 kg
2.27 kg
6.18 kg

34

Ťažká

What type of refrigerant is R32?


Carbon dioxide
Hydrofluorocarbon
Hydrocarbon
Hydrofluoroolefin

35

Ťažká

What hazards do A2L refrigerants pose?


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

36

Ťažká

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


Phosgene is produced
Hydrogen fluoride is produced
Citric acid is produced
Nitrous oxide 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
Half
Twice
Seven times

38

Ťažká

What is the GWP value for R32?


3
7
675
0

39

Ťažká

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


Because these systems never have liquid receivers
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

40

Ťažká

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


To ensure that the discharge pressure never becomes excessive
To dilute the refrigerant in the event of a leak
To reduce energy consumption
To prevent the build-up of contaminants in the condenser

41

Ťažká

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


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

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?


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

44

Ťažká

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


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

45

Ťažká

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


Merely a reduction in efficiency
Risk of leakage and the formation of an explosive mixture
No impact on safety
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
Regulating compressor capacity
Measuring the refrigerant temperature
Monitoring pipe pressure

47

Ťažká

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


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

48

Ťažká

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


Anywhere in the room
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
Near the control panel

49

Ťažká

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


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

50

Ťažká

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


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

51

Ťažká

Gas detectors should be installed in rooms where:


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

52

Ťažká

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


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

53

Ťažká

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


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

54

Ťažká

How do leaks affect systems using flammable refrigerants?


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

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 increases efficiency
It has no effect

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
Causes leaks
It increases the pressure

57

Ťažká

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


Disabling safety devices
Lack of servicing
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 doesn’t matter
It increases the amount of refrigerant

59

Ťažká

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


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

60

Ťažká

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


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

61

Ťažká

What hazards are associated with a Class A3 safety agent?


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

62

Ťažká

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


0
3945
675
6

63

Ťažká

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


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


50%
150%
600%
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