1

Nehéz

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

Nehéz

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

3

Nehéz

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


2 m
1 m
0.5 m
3 m

4

Nehéz

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
20 kg
33 kg
18 kg

5

Nehéz

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
1.5 kg
1.0 kg
10 kg

6

Nehéz

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


There is no need to evacuate such systems
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
Position the vacuum pump 3 metres above floor level

7

Nehéz

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


A fire extinguisher
Tinted safety goggles
Thick gloves
Fire blanket

8

Nehéz

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
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 and drain the system

9

Közepes

What is R1270?


Isobutane
Butane
Propene
Propylen

10

Nehéz

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

Nehéz

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


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

12

Nehéz

Which of the following is a source of ignition?


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

13

Nehéz

What substance is produced when R32 is burnt?


Hydrochloric acid
Phosgene
Carbon monoxide
Hydrogen fluoride

14

Nehéz

What type of refrigerant is R1234ze?


Hydrochlorofluoro-hydrocarbon
Hydrofluoroolefin
Chloro-fluoro-hydrocarbon
Hydrocarbon

15

Nehéz

What hazards does a Group A3 refrigerant pose?


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

16

Nehéz

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

Nehéz

What is the cooling capacity of R32 compared to R410A?


60%
75%
105%
130%

18

Nehéz

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 energy-efficient
Because they are more reliable
Because they must be kept running continuously to disperse the leaking refrigerant

19

Nehéz

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 affects energy efficiency
Because it increases operating pressures

20

Nehéz

What is the GWP value for R290?


A. 0.02
675
7
3

21

Nehéz

Which of the following is not a source of ignition?


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

22

Nehéz

What is R290?


Ethane
Propylene
Propene
Butane

23

Nehéz

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
1.5 kg
1.0 kg

24

Nehéz

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


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

25

Nehéz

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

Nehéz

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


8 kg
17 kg
20 kg
3.6 kg

27

Nehéz

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
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 systems containing R290

28

Nehéz

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


Thick gloves
A fire extinguisher
Tinted safety goggles
Fire blanket

29

Nehéz

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
Work outdoors
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

30

Nehéz

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
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
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

31

Nehéz

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


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

32

Nehéz

Why can’t recovery stations designed for HFCs be used with 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
The recovery unit cannot withstand the working pressure of R600a

33

Nehéz

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
6.18 kg
227 kg
2.27 kg

34

Nehéz

What type of refrigerant is R32?


Carbon dioxide
Hydrofluoroolefin
Hydrofluorocarbon
Hydrocarbon

35

Nehéz

What hazards do A2L refrigerants pose?


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

36

Nehéz

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


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

37

Nehéz

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?


Half
Twice
Seven times
The same

38

Nehéz

What is the GWP value for R32?


0
675
3
7

39

Nehéz

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

Nehéz

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


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

41

Nehéz

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

Nehéz

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


It reduces the system’s efficiency
It may lead to the use of tools that are a source of ignition
It may lead to the incorrect selection of oil
It has no significant impact on safety

43

Nehéz

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


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

44

Nehéz

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


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
Labelling is not required for hermetically sealed systems

45

Nehéz

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


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

46

Nehéz

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


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

47

Nehéz

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


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

48

Nehéz

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


Near the control panel
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
Anywhere in the room

49

Nehéz

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


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

50

Nehéz

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


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

51

Nehéz

Gas detectors should be installed in rooms where:


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

52

Nehéz

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

53

Nehéz

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

Nehéz

How do leaks affect systems using flammable refrigerants?


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

55

Nehéz

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

Nehéz

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


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

57

Nehéz

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


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

58

Nehéz

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


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

59

Nehéz

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


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

60

Nehéz

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


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

61

Nehéz

What hazards are associated with a Class A3 safety agent?


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

62

Nehéz

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


3945
6
675
0

63

Nehéz

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

64

Nehéz

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


Similar
600%
50%
150%