Tesztek

F-Gas English Low GWP

Minden kérdés
HFC | Flammable | CO₂ | NH₃
Könnyű kérdések | Közepes nehézségű kérdések | Nehéz kérdések

1

Könnyű

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


Pound
kg
t
N

2

Közepes

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


The refrigerant releases the heat absorbed in the compressor via the condenser
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.
In the condenser, the refrigerant releases the heat absorbed in the evaporator into the surroundings.
The medium flowing through the evaporator (glycol, water) condenses, whilst the refrigerant evaporates.

3

Közepes

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


On the compressor and discharge temperatures
On the evaporation (boiling) temperature.
On the ambient temperature.
On the superheat temperature.

4

Közepes

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


Yes, but only when using HFC refrigerants.
The heat flow balances the energy input.
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.

5

Közepes

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


Pay attention to the fan’s operation and the ambient temperature.
You should ensure the general maintenance of the condenser and keep the heat exchange surfaces clean.
Care should be taken to ensure that the air temperature at the condenser inlet is lower than the air temperature at the condenser outlet.
Ensure that the air temperature at the condenser outlet is higher than the condensation temperature.

6

Közepes

What criteria should be considered when selecting a suitable condenser?


The required capacity of the condenser and the technical specifications declared by the manufacturer 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.
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.

7

Közepes

How do contaminants (dust, particulates, deposits) affect the performance and efficiency of 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 a reduction in condensing pressure.
Contaminants do not significantly affect the efficiency and effectiveness of the heat exchange surfaces in condensers.
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.

8

Közepes

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


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

9

Közepes

What can cause frost to form on the evaporator?


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

10

Közepes

What happens when the evaporation temperature drops?


The compressor’s cooling capacity increases.
The compressor’s cooling capacity decreases.
The discharge temperature decreases.
The condenser fan speed increases.

11

Közepes

When is defrosting using the refrigerant possible?


Never. We use electricity for defrosting (for example, using a special electric heater).
Only when using speed-controlled fans.
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.

12

Közepes

When can frost form on the evaporator surface?


Frost forms only when the refrigeration system is operating continuously.
Frost always forms on air coolers.
In the case of finned evaporators.
Only in the case of air coolers, when the air temperature drops below 0°C.

13

Közepes

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.
additional cooling.
using larger-diameter pipes.
using smaller-diameter pipes.

14

Közepes

How does hot gas defrosting of the evaporator work?


We switch on the gas heater directed at the evaporator.
We swap the outlet and inlet sides of the evaporator.
Heated vapour (hot gas) from the compressor is directed into the evaporator piping.
This involves reversing the direction of rotation of the compressor.

15

Közepes

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


It evaporates the water flowing through the evaporator.
It ensures that the refrigerant is superheated over the largest possible heat exchange surface area.
Thanks to the evaporator, the cooled medium transfers heat to the boiling refrigerant.
It cools the refrigerant.

16

Közepes

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


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.
The electric heaters must be in contact with the evaporator’s heat exchange surface (the heater must touch the fins).
Thanks to the forced air flow created by the fans, the heat from the heaters is transferred to the heat exchanger.

17

Közepes

Refrigerant distributor:


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

18

Közepes

What are the possible methods of defrosting air coolers?


Electric defrosting only.
Electric defrosting, liquid defrosting or defrosting using hot refrigerant vapour.
Natural defrosting; there are no other effective methods.
Hot gas defrosting.

19

Közepes

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


Falls.
Rises.
Remains constant.
It behaves differently depending on the ambient temperature.

20

Közepes

MOP in thermostatic expansion valves stands for:


maximum operating pressure.
minimum flow opening.
self-cleaning of the valve in the event of moisture in the refrigerant freezing.
maximum pressure switch protection.

21

Közepes

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


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.
to consistently adjust the evaporation pressure in the condenser depending on the temperature of the refrigerant vapour leaving the condenser.
to control the amount of refrigerant supplied to the evaporator depending on the superheat of the vapour leaving that heat exchanger.

22

Közepes

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


An electronically commutated motor approved for use with the compressor should be used.
A low-speed motor should be used.
A motor with low starting torque can be used.
A motor with high starting torque must be used.

23

Közepes

What does the thermostatic expansion valve regulate?


Cooling.
Discharge temperature.
Evaporation pressure after.
The mass flow of the refrigerant injected into the evaporator.

24

Közepes

The refrigerant absorbs heat when...


it evaporates.
it condenses.
freezes.
sublimates

25

Közepes

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


...the static superheat of the valve.
  ...the degree to which the valve is filled with refrigerant liquid.
...the superheat value during valve operation.
…the degree of refrigerant expansion.

26

Közepes

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


Charging with refrigerant takes place during operation via the outlet connection of the refrigerant capillary tube.
in any way.
behind the condenser to the liquid refrigerant receiver.
to the suction side of the compressor.

27

Közepes

What does a thermostatic/electronic expansion valve regulate?


The amount of refrigerant by controlling the evaporator superheat.
The evaporation pressure, closing when it falls below the setpoint temperature.
The number of revolutions of the compressor per unit of time.
Condenser subcooling by adjusting the condensing pressure.

28

Közepes

What does the MOP function in expansion valves mean?


This means that these expansion valves are set to prevent overheating.
It means that these expansion valves are set to limit the maximum operating pressure.
This means that these expansion valves are set to limit subcooling.
This means that these expansion valves are set to a specific suction pressure.

29

Közepes

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


... 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, and the lower the system’s energy efficiency will be.
  ...the lower the theoretical coefficient of cooling efficiency qo will be, whilst the cooling capacity Qo remains unchanged.
...the lower the theoretical coefficient of refrigeration efficiency qo will be, and the lower the refrigeration capacity Qo will be.

30

Közepes

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


...must be approximately 5 K lower.
The value of the MOP point is irrelevant.
...must be approximately 7 K higher.
...must be approximately 7 K lower.

31

Közepes

What is the function of the suction pressure regulator?


It limits the suction pressure and protects the compressor from excessively high suction pressure.
It prevents a drop in suction pressure and, if necessary, shuts down the refrigeration system.
To maintain the suction pressure at the highest possible level.
It maintains the suction pressure at a constant level.

32

Közepes

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


To maintain the condensing pressure at the highest possible level.
To maintain the condensing pressure at the lowest possible level.
To maintain the condensing pressure at a constant level.
To maintain the water temperature at the highest level.

33

Közepes

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

Közepes

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

Közepes

When do we encounter the superheated state?


It is a condition in which the compressor motor temperature rises excessively.
It is the temperature difference between the evaporation temperature and the ambient temperature.
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

Közepes

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


We check using a liquid pressure gauge.
We are unable to check this.
We check this using a sight glass.
We check using a pressure gauge fitted on the discharge side of the compressor.

37

Közepes

The liquid lines are located...


between the compressor and the condenser.
between the condenser and the liquid receiver.
between the evaporator and the regenerative heat exchanger.
between the evaporator and the compressor.

38

Közepes

What is the function of the liquid receiver in a 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.
The tank is used to collect the liquid refrigerant and excess oil in the system.
The reservoir is used to further cool the liquefied refrigerant leaving the condenser.
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.

39

Közepes

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

Közepes

Where should the liquid receiver be installed?


It should be installed downstream of the condenser, upstream of the expansion valve.
It should be fitted just before the compressor.
It should be fitted after the evaporator.
It should be fitted between the compressor and the condenser.

41

Közepes

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

Közepes

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


A reduction in the system’s energy efficiency.
An increase in the amount of refrigerant in the system and an increase in condensing pressure.
There is no effect whatsoever on either the amount of refrigerant or energy efficiency.
A reduction in the amount of refrigerant and an increase in energy efficiency.

43

Közepes

Which refrigerants belong to the HFC group?


R11, R12, R502.
R22, R401A.
R134a, R404A, R507A, R410A.
R134a, R32, R22, R507A, R290.

44

Közepes

Which refrigerants belong to the HFO group?


R1234yf, R1234ze.
R22, R12.
R134a, R290.
R134a, R404A.

45

Közepes

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 R407C refrigerant is much higher than that of R410A.
The saturation pressure of both refrigerants is roughly the same.

46

Közepes

What does the TEWI parameter define?


It is the global warming potential, expressed in terms of carbon dioxide (CO₂), over a 100-year time horizon.
This is a parameter that quantifies the impact of refrigerants on the ozone layer.
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).

47

Közepes

What are the characteristics of R452A refrigerant compared to R404A?


The temperature glide of R452A is half that of 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.

48

Közepes

What is the distinguishing feature of R1234yf compared to R134a?


greater flammability.
A higher critical temperature.
greater toxicity.
a higher boiling point at standard pressure.

49

Közepes

Compared to R134a, the refrigerant CO₂ is characterised by?


It has a temperature slip of 7K greater than R134a.
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 lower critical temperature, higher operating pressures and greater volumetric efficiency, allowing for the use of a smaller quantity of refrigerant compared to R134a.

50

Közepes

The following are not classified as fluorinated greenhouse gases:


Sulphur hexafluoride (SF6).
Hydrofluorocarbons (HFCs).
Carbon dioxide (CO₂).
Perfluorocarbons (PFCs).

51

Nehéz

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


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

52

Nehéz

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

53

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
3 m
0.5 m
1 m

54

Nehéz

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


33 kg
20 kg
18 kg
9 kg

55

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?


10 kg
1.5 kg
2.5 kg
1.0 kg

56

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
Position the vacuum pump 3 metres above floor level
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

Közepes

What is the greenhouse effect?


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).
It causes the thermal radiation emitted by the Earth to be trapped in the upper atmosphere.
It alters the composition of the atmospheric air.

58

Nehéz

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


A fire extinguisher
Fire blanket
Thick gloves
Tinted safety goggles

59

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
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

60

Közepes

What is R1270?


Propene
Propylen
Butane
Isobutane

61

Nehéz

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


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

62

Nehéz

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


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

63

Nehéz

Which of the following is a source of ignition?


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

64

Nehéz

What substance is produced when R32 is burnt?


Phosgene
Hydrochloric acid
Hydrogen fluoride
Carbon monoxide

65

Nehéz

What type of refrigerant is R1234ze?


Hydrocarbon
Hydrofluoroolefin
Chloro-fluoro-hydrocarbon
Hydrochlorofluoro-hydrocarbon

66

Nehéz

What hazards does a Group A3 refrigerant pose?


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

67

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)?


1.0 kg
4.93 kg
0.285 kg
1.5 kg

68

Könnyű

What does the GWP indicator mean?


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).
This is an indicator expressing the potential to deplete the ozone layer.
It is an expansion of the abbreviation ‘Global Warming Potential’ and indicates the rate of increase in air temperature
It is a unit expressing the ability to enhance the ozone layer.

69

Nehéz

What is the cooling capacity of R32 compared to R410A?


130%
105%
75%
60%

70

Nehéz

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


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

71

Nehéz

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


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

72

Nehéz

What is the GWP value for R290?


675
A. 0.02
7
3

73

Nehéz

Which of the following is not a source of ignition?


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

74

Nehéz

What is R290?


Propene
Ethane
Butane
Propylene

75

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?


1.5 kg
2.5 kg
1.0 kg
150 g

76

Nehéz

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

77

Nehéz

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
5 m
1 m
10 m

78

Nehéz

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


17 kg
3.6 kg
20 kg
8 kg

79

Közepes

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


Refrigeration equipment emits CO₂ both directly and indirectly.
As a result of oil being emitted into the atmosphere by the condenser and filter
Indirectly (through energy consumption) and directly (through the emission of refrigerants into the atmosphere)
Through the leakage of refrigerant into the environment.

80

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

81

Nehéz

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


Tinted safety goggles
Fire blanket
Thick gloves
A fire extinguisher

82

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
Purge the system with oxygen-free nitrogen
Work outdoors
You must not desolder joints on a system containing a flammable refrigerant; they must be cut using a pipe cutter

83

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?


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
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

84

Nehéz

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


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

85

Nehéz

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

86

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)?


227 kg
618 kg
2.27 kg
6.18 kg

87

Nehéz

What type of refrigerant is R32?


Hydrocarbon
Hydrofluorocarbon
Hydrofluoroolefin
Carbon dioxide

88

Nehéz

What hazards do A2L refrigerants pose?


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

89

Nehéz

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


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

90

Közepes

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


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.
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).
The absorption of radiation reaching the Earth’s surface.

91

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?


The same
Twice
Seven times
Half

92

Nehéz

What is the GWP value for R32?


675
0
7
3

93

Nehéz

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
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
Due to lower operating pressures

94

Nehéz

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

95

Közepes

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


Directive 2009/125/EC
Regulation (EU) 2024/573
Regulation (EU) No 517/2014
Regulation (EU) 2015/1188

96

Közepes

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


Prevention of F-gas emissions and the achievement of the EU’s climate targets
To reduce taxes on refrigeration equipment
To facilitate the import of electrical appliances
Standardising metal recycling standards

97

Közepes

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


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 use energy labels, and this is regulated by Regulation (EU) 2024/573
Manufacturers are only required to declare the quantity of F-gas used, in accordance with Regulation (EU) No 517/2014

98

Közepes

What is the main objective of the Ecodesign Directive?


To facilitate the import of products from outside the EU
To increase sales of electrical appliances in 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

99

Közepes

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


Enables the refrigerant flow to be completely shut off
It measures the moisture content of the refrigerant
It prevents excessive pressure build-up in the system
It regulates the temperature of the refrigerant

100

Könnyű

What is the main function of a relief valve?


Prevents the evaporator from freezing
It controls the oil level in the compressor
Relieves pressure in the system in the event of excessive pressure
It monitors the moisture content of the refrigerant

101

Közepes

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


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

102

Közepes

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


To measure the condenser temperature
To regulate compressor pressure
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

103

Közepes

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


It restricts oil flow
Controls the operation of the compressor and valves to maintain the set temperature
It drains excess refrigerant into the receiver
To maintain a constant pressure in the compressor

104

Nehéz

What is the role of the liquid 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
Heats the refrigerant before it enters the evaporator
It separates the liquid from the oil

105

Nehéz

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


Heats the refrigerant before it enters the evaporator
It prevents liquid from entering the compressor
Separates oil from the refrigerant and facilitates the return of oil to the compressor
They are used solely to measure the moisture content of the refrigerant

106

Közepes

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


They control the pressure in the condenser
They drain off excess refrigerant
Maintains the correct oil level in the compressor
They control the evaporator temperature

107

Közepes

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


Regulates the oil flow
Stores excess refrigerant and facilitates the detection of leaks
It controls the evaporator temperature
It maintains a constant pressure in the system

108

Közepes

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


Relieves pressure in the system in the event of excessive pressure
It monitors the moisture content of the refrigerant
Measures the refrigerant temperature at the compressor inlet and outlet, which helps to identify leaks
Controls the oil level

109

Közepes

What is the role of the defrost control valves?


They control the pressure in the compressor
They are used to monitor the moisture content of the refrigerant
Protect the evaporator from excessive icing and reduce the risk of leaks
They drain off excess oil

110

Nehéz

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


CO₂ is flammable, so separators cannot be used
CO₂ operates at high pressure, which increases the risk of compressor failure and leaks
CO₂ cannot be used in systems with sight glasses
CO₂ does not require lubrication, so separators are unnecessary

111

Nehéz

What is the critical pressure of CO₂ (R744)?


Approximately 10 bar
Approximately 74 bar
Approximately 31 bar
Approximately 120 bar

112

Könnyű

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


Psi
bar
Pa
Atm.

113

Közepes

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


In the Vienna Convention for the Protection of the Ozone Layer.
In the Regulation of the Minister for the Economy on the introduction of a list of fluorinated greenhouse gases.
In the Act on Ozone-Depleting Substances and Certain Fluorinated Greenhouse Gases.
In Regulation (EU) No 2024/573 of the European Parliament and of the Council

114

Nehéz

What characterises the transcritical process in CO₂ systems?


The system operates above the critical point and the refrigerant does not condense in the conventional manner
It occurs only at low temperatures
It is irrelevant to the operation of the system
Conventional condensation occurs

115

Nehéz

What characterises the subcritical CO₂ process?


Operation above the critical point
The absence of condensation
The conventional condensation process below the critical point
The absence of evaporation

116

Nehéz

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


To measure temperature
For analysing thermodynamic processes in a refrigeration system
To regulate pressure
To detect leaks

117

Nehéz

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


Only the amount of refrigerant
Pressure, enthalpy, temperature and state of the refrigerant
Only the humidity
Only the temperature

118

Nehéz

What are CO₂ saturation tables used for?


To determine the relationship between temperature and pressure at saturation
To regulate the compressor
To measure humidity
To determine the oil quantity

119

Nehéz

What does the CO₂ saturation state mean?


A state in which the refrigerant is only a gas
A state of high pressure
Equilibrium between the liquid and vapour phases
Dry ice state

120

Nehéz

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

Nehéz

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


Blocked pipes and system damage
No risk
Pressure reduction
Improved efficiency

122

Nehéz

How does the CO₂ pressure change as the temperature rises?


It remains the same
It decreases
It first decreases, then increases
Rises sharply

123

Nehéz

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


As CO₂ systems operate in different modes (sub- and transcritical) and require detailed analysis
It doesn’t matter
It only applies to NH₃
It is only used for design purposes

124

Közepes

Where can I find the lists specifying controlled substances?


In Regulation (EU) No 2024/590 of the European Parliament and of the Council.
In the current Act on Ozone-Depleting Substances and Certain Fluorinated Greenhouse Gases.
In the Regulation of the Minister for the Environment on the list of controlled substances.
In the Vienna Convention for the Protection of the Ozone Layer.

125

Nehéz

What happens to CO₂ above the critical point?


It ceases to conduct heat
It turns into a solid
It turns into a liquid
It transitions to a supercritical state (no distinction between liquid and gas)

126

Nehéz

Why do CO₂ systems require precise pressure control?


Due to significant pressure changes with temperature fluctuations
They do not require control
Because there are no valves
Due to low pressures

127

Közepes

Why is ammonia (NH₃) considered a toxic refrigerant?


It does not react with water, which makes it difficult to neutralise
It is highly irritating to the respiratory tract and toxic if inhaled
It is flammable and can form explosive mixtures with air
It is colourless and odourless, so it is difficult to detect

128

Nehéz

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


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

Nehéz

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
Atmospheric pressure, approximately 1 bar
Positive pressure, in the range of 5–10 bar
Negative pressure (vacuum), below 0 bar

130

Nehéz

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


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

131

Nehéz

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


Charging should take place in a well-ventilated area using appropriate personal protective equipment
Charging can be carried out without personal protective equipment
NH₃ can be charged together with air
Charging must only take place at temperatures below 0°C

132

Nehéz

How should oil be handled in systems using R717?


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
Oil has no effect on the system’s operation
Oil can be mixed with any refrigerant

133

Nehéz

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


Recovery is not required
The refrigerant can be drained into the sewer system
The gas can be released into the atmosphere
The refrigerant must be recovered into suitable, leak-proof tanks designed for NH₃

134

Nehéz

How should R717 (NH₃) be stored?


In any open containers
Near heat sources
In unmarked plastic containers
In sealed, labelled containers, in a cool and well-ventilated place

135

Közepes

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


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.
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 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)

136

Nehéz

What should be done in the event of R717 contamination?


Add water to dilute it
The refrigerant must be purified or sent for disposal in accordance with regulations
Continue to use without restriction
Release into the atmosphere

137

Nehéz

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


Toxic to humans and may cause chemical burns
Increased cooling efficiency
Damage to electrical equipment only
No risk whatsoever

138

Nehéz

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


Close your eyes and carry on working
Increase the pressure in the system
Evacuate personnel immediately and remove the source of the leak, if it is safe to do so
Ignore it and carry on working

139

Nehéz

What role do scrubbers play in NH₃ systems?


They store the refrigerant
They are used to measure temperature
They increase the pressure in the system
Neutralises ammonia through absorption in a liquid (e.g. water)

140

Nehéz

How should the system be prepared before filling with R717?


Simply start it up
There is no need to check it
The pressure must be increased above the standard level
Check for leaks, remove air and moisture, and create a vacuum

141

Nehéz

What are the transport requirements for R717?


Must be transported in suitable, labelled containers in accordance with ADR regulations
Transport is not subject to regulations
It can be transported without labelling
It can be transported in open containers

142

Nehéz

What personal protective equipment is required when working with NH₃?


Only a safety helmet
Workwear only
Safety goggles, gloves and respiratory protective equipment
No requirements

143

Közepes

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


Installation without filters
Installation without a leak test
Correctly create a vacuum and remove moisture from the system
Increasing the amount of refrigerant

144

Közepes

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


It has no effect
Ensures proper lubrication and improves energy efficiency
It reduces cooling capacity
Causes a rise in pressure

145

Közepes

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


They improve efficiency
Have no effect
They lower the operating temperature
These cause a drop in performance and an increase in energy consumption

146

Közepes

Regulation (EC) No 2024/590 relates to:


Ozone-depleting substances.
Alternative refrigerants serving as substitutes for fluorinated greenhouse gases.
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.

147

Közepes

What is the significance of regulating suction and discharge pressure?


Causes leaks
It has no effect on efficiency
Helps maintain optimal operating conditions for the compressor
Increases oil consumption

148

Közepes

What maintenance measure reduces the compressor’s energy consumption?


Disabling safety devices
Increasing the refrigerant charge
Lack of servicing
Regular replacement of filters and dryers

149

Közepes

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


It has no effect
Reduces energy consumption
It improves efficiency
Leads to increased pressure and reduced efficiency

150

Közepes

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


It increases the amount of refrigerant
Causes leaks
It doesn’t matter
Enables optimisation of operation and a reduction in energy consumption

151

Közepes

How does refrigerant superheat at the compressor suction affect performance?


It has no effect
Excessive overheating reduces efficiency and increases energy consumption
It only causes a drop in temperature
It always improves performance

152

Közepes

How does the correct layout of the system affect efficiency?


It causes the temperature to rise
It increases the pressure
Shortens flow paths and reduces energy losses
It doesn’t matter

153

Közepes

How important is pipe insulation?


It has no effect
Reduces heat loss and improves energy efficiency
It increases energy consumption
Causes a rise in pressure

154

Közepes

Which measure most improves the condenser’s energy efficiency?


Restricted airflow
Increasing the amount of refrigerant
Regular cleaning of heat exchange surfaces
Contamination of the heat exchange surface

155

Közepes

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


Causes an increase in pressure and energy consumption by the compressor
It has no effect
It lowers the condensing pressure
It improves efficiency

156

Közepes

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


It doesn’t matter
Insufficient airflow reduces efficiency
Causes a drop in pressure
Ensures effective heat dissipation and improves energy efficiency

157

Közepes

Which refrigerants cause damage to the ozone layer?


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.
All refrigerants that contain chlorine or bromine in their molecules.

158

Közepes

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


It has no effect
Impairs heat exchange and increases energy consumption
It lowers the condensation temperature
It improves heat transfer

159

Közepes

How does correct condensation pressure control affect efficiency?


It has no effect
Maintains optimum operating conditions and reduces energy consumption
Causes leaks
It increases energy consumption

160

Közepes

How do condenser leaks affect energy efficiency?


They lower the temperature
Have no effect
They improve efficiency
Causes refrigerant loss and a drop in efficiency

161

Közepes

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


It should be close to heat sources
It doesn’t matter
It should be installed in a well-ventilated area with unobstructed airflow
It should be housed in a small room

162

Közepes

How does hot air recirculation affect the condenser?


Impairs cooling and increases energy consumption
It improves efficiency
It reduces the pressure
It has no effect

163

Közepes

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


It increases the pressure
It impairs cooling
Reduces energy losses and improves the efficiency of the entire system
It doesn’t matter

164

Közepes

Which measure most improves the energy efficiency of the evaporator?


Increasing the condensation temperature
Restricted airflow
Increasing the amount of refrigerant
Regular defrosting of the evaporator

165

Közepes

How does evaporator icing affect the system’s operation?


It has no effect
It improves cooling performance
It lowers the condensation temperature
Impairs heat exchange and increases energy consumption

166

Közepes

How does dirt on the evaporator surface affect its performance?


It reduces the pressure
It improves efficiency
Impairs heat exchange and increases energy consumption
It has no effect

167

Közepes

What maintenance task is crucial for the evaporator?


Reduced airflow
Increasing the refrigerant charge
Lack of maintenance
Regular cleaning and defrosting

168

Közepes

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


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.
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.

169

Közepes

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


It only causes a drop in temperature
Excessive superheat reduces energy efficiency
It has no effect
It always improves performance

170

Közepes

How do leaks in the evaporator affect efficiency?


These cause refrigerant loss and a drop in efficiency
Increase capacity
Improves performance
Have no effect

171

Közepes

How important is correct expansion valve adjustment?


Ensures optimal evaporator charge and improves efficiency
It doesn’t matter
Causes leaks
It increases energy consumption

172

Közepes

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


It lowers the condensation temperature
Causes cooling losses and increased energy consumption
It improves efficiency
It has no effect

173

Közepes

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


It has no effect
It increases energy consumption
Causes leaks
Ensures optimum superheat and improves system efficiency

174

Közepes

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


It has no effect
The refrigerant charge will increase
Efficiency will drop because the evaporator is not being fully utilised
Cooling efficiency will improve

175

Közepes

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


It may lead to improved efficiency, but it increases the risk of the compressor becoming flooded with liquid
It reduces refrigerant flow
It has no effect
It increases operational safety

176

Közepes

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


They improve its performance
Have no effect
They can cause it to become blocked and reduce efficiency
They lower the temperature

177

Közepes

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


It doesn’t matter
It lowers the temperature
It increases the amount of refrigerant
Removes moisture and contaminants, improving the system’s efficiency

178

Közepes

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 doesn’t matter
It increases energy consumption

179

Közepes

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


The Regulation sets out requirements relating to brazing of refrigeration systems.
The Regulation sets out health and safety requirements for soldering work.
The Regulation concerns gases that contribute to the greenhouse effect.
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

Közepes

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 has no effect
It increases energy consumption
It causes a significant rise in temperature

181

Közepes

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


It lowers the temperature
It increases the amount of refrigerant
Ensures the system is matched to its capacity and operates optimally
It doesn’t matter

182

Közepes

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


Lower energy efficiency
The need for explosion-proof measures due to the flammability of the refrigerant
Higher operating pressures
No need for safety measures

183

Közepes

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


They must operate at higher pressures
No differences
They must be designed to operate with flammable refrigerants (e.g. hermetic compressors)
They do not require lubrication

184

Nehéz

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


Low operating pressures
Very high operating pressures
No need for regulation
Low energy efficiency

185

Nehéz

What are the requirements for piping materials in CO₂ systems?


They must be made exclusively from plastics
It does not matter
They must be able to withstand high pressures (e.g. high-grade steel)
They may be made of any material

186

Nehéz

How does a booster system work in CO₂ installations?


It is used to store the refrigerant
It utilises two stages of compression (low and medium pressure) in a single system
It reduces the pressure in the evaporator
It reduces the amount of refrigerant

187

Nehéz

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


They lower the evaporator temperature
They are used to store the refrigerant
They control the pressure on the high-pressure side and optimise system operation
They regulate oil flow

188

Nehéz

Why is pressure optimisation in CO₂ systems crucial?


It enables the system to achieve maximum energy efficiency
It doesn’t matter
It reduces the ambient temperature
It reduces the amount of refrigerant

189

Nehéz

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


They lower the ambient temperature
They increase energy consumption
They enable gas recovery from the medium-pressure stage and improve efficiency
It does not matter

190

Közepes

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


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

191

Nehéz

How does an ejector work in a CO₂ system?


It uses the energy of the higher-pressure refrigerant to raise the pressure of the refrigerant from the lower stage, which improves efficiency
Stores the refrigerant
It lowers the evaporator temperature
It increases the amount of refrigerant

192

Nehéz

What is the function of liquid ejectors in CO₂ systems?


They raise the refrigerant temperature
They reduce atmospheric pressure
They increase the amount of oil
They assist with liquid recovery and improve evaporator feed

193

Nehéz

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


The presence of liquid in the evaporator, which improves heat transfer and efficiency
Lack of regulation
The absence of liquid in the evaporator
Low operating pressure

194

Nehéz

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


Increased efficiency
A drop in temperature
A decrease in refrigerant quantity
A rise in pressure resulting from the refrigerant heating up whilst at rest

195

Nehéz

How can standstill pressure in CO₂ systems be reduced?


By shutting down the system completely
By increasing the refrigerant charge
By using parallel compressors and external cooling systems
By increasing the temperature

196

Nehéz

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


A drop in temperature
A lack of refrigerant flow, which can lead to increased pressure and safety risks
Normal system operation
Improved efficiency

197

Nehéz

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


Due to the need for precise control of pressure and temperature
They do not require automation
Because there are no valves
Due to low pressures

198

Nehéz

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
Net weight only
Information about the cylinder owner
Agent name only

199

Nehéz

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 reduces the system’s efficiency
It may lead to the incorrect selection of oil

200

Nehéz

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


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

201

Közepes

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

Nehéz

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


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

203

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
No impact on safety
Risk of leakage and the formation of an explosive mixture

204

Nehéz

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


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

205

Nehéz

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


Once every 5 years
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

206

Nehéz

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


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
Anywhere in the room
Only at the entrance to the room

207

Nehéz

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


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

208

Nehéz

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


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

209

Nehéz

Gas detectors should be installed in rooms where:


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

210

Nehéz

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
Exits do not need to be signposted if the room is small
One exit with an information sign about the refrigerant
One exit, clearly marked in the direction of escape

211

Nehéz

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


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

212

Közepes

What information must appear on the unit’s 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.
It does not matter what should be included on the device 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

213

Nehéz

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

214

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

215

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

216

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

217

Nehéz

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


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

218

Nehéz

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


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

219

Nehéz

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


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

220

Nehéz

Which safety class applies to R744?


A2
B2L
A3
A1

221

Nehéz

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


A two-phase mixture at intermediate pressure
A subcooled liquid
A supercritical fluid
Saturated vapour at intermediate pressure

222

Nehéz

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


The pressure in the gas cooler
The outlet temperature of the gas cooler
The inlet temperature to the gas cooler
The gas cooler fans

223

Közepes

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


°C
°F
K
°R

224

Közepes

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


Operator details, unit details, type and quantity of refrigerant, information regarding servicing and repairs.
Information regarding refrigerant recovery and unit dismantling.
The owner, installer and service technician of the unit.
The make and model of the unit, so that the manufacturer can be contacted to obtain the technical information necessary for servicing.

225

Nehéz

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

226

Nehéz

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


They have good low-temperature performance
They can withstand higher pressures
They bend easily
They come in a wider range of diameters

227

Nehéz

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


All Schrader valve cores are suitable for all refrigerants
Hydrocarbons leak through Schrader valves
When brazing the valve body to the system, the core must be removed, then refitted and tightened to the correct torque
Schrader valves must not be used in R744 systems

228

Nehéz

Which refrigerant can be detected using phenolphthalein paper?


R1234ze
R1270
R744
R717

229

Nehéz

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


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

230

Nehéz

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


It has a higher pressure than pure nitrogen
It is non-flammable
It has smaller molecules and diffuses more easily
It has a distinct odour

231

Nehéz

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 ensure that R744 is charged slowly
To prevent the formation of dry ice
To prevent damage to the compressor

232

Nehéz

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


Reduced cooling capacity
Excessively high discharge pressure
The formation of hydrogen fluoride, which will decompose into hydrofluoric acid and damage the compressor
The formation of carbonic acid, which will cause damage to the system

233

Nehéz

Which system may require manual oil recovery?


An R717 system
Supercritical ‘booster’ system using R744
R744 cascade system
Secondary system using R744

234

Nehéz

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


56 bar g
14 bar g
25 bar g
90 bar g

235

Közepes

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


The equipment maintenance technician.
The person responsible for risk assessment.
The operator of the unit or system.
There is no such obligation.

236

Nehéz

Which refrigerant is lighter than air?


R1270
R744
R717
R1234ze

237

Nehéz

What hazards are associated with a Class A3 safety agent?


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

238

Nehéz

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


3945
675
6
0

239

Nehéz

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

240

Nehéz

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


Similar
50%
150%
600%

241

Nehéz

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


The same as the pressure set on the relief valve
The same as the high-pressure setting on the pressure switch
27.5 bar g
Higher than the maximum permissible pressure in the low-pressure stage

242

Nehéz

What is the correct definition of critical temperature?


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

243

Nehéz

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


it loses heat as its temperature drops
loses heat at constant temperature and pressure
it loses heat when its pressure drops
loses heat during a phase change

244

Nehéz

R717 is highly corrosive to


titanium
aluminium
copper
stainless steel

245

Nehéz

What is the effect of repeatedly opening the relief valve?


The valve remains fully open continuously
The relief pressure rises
The valve will not open
The relief pressure drops

246

Közepes

Oil traps on the suction pipework are required:


before the compressor.
before the safety valve.
at the inlet to each component of the refrigeration system.
always before any rise in the pipeline.

247

Nehéz

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 = (P1 × T1)/T2
P2 = T2/(P1 × T1)
P2 = T1/(P1 × T2)
P2 = (P1 × T2)/T1

248

Nehéz

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


500,000 ppm
500 ppm
5,000 ppm
50,000 ppm

249

Nehéz

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


Because compressors with a separate motor are cheaper
To reduce the condensing pressure
Because NH₃ reacts with the motor windings and hermetic compressors are not used
To increase the amount of refrigerant in the system

250

Nehéz

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


Diaphragm compressor
Hermetic scroll
Rotary vane compressor
A reciprocating or screw compressor

251

Nehéz

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

Nehéz

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


By adjusting the oil level
By using a slide valve
By closing the suction valve
By changing the type of oil

253

Nehéz

When is two-stage compression used in NH₃ systems?


Only with water-cooled condensers
Exclusively in small systems
At small temperature differences
At very low vapour pressures and high pressure differentials

254

Nehéz

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


No need for a separator
Higher energy consumption
Lower efficiency
Higher efficiency and lower discharge temperature

255

Nehéz

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 transfers heat only to the air
It does not require a water supply

256

Nehéz

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


Regulates the condensing pressure
It separates oil from the refrigerant
It prevents liquid from entering the compressor
Increases the discharge temperature

257

Közepes

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


When the sight glass is full of liquid refrigerant and we observe a rise in the oil level in the compressor sump.
When we observe a rise in the refrigerant level in the liquid receiver and the subcooling increases.
When the condensing pressure and suction pressure rise, but there is no superheat.
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.

258

Nehéz

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


To increase the oil volume
To control the condenser fan
To maintain the correct refrigerant level and prevent the compressor from flooding
To reduce the condensing temperature

259

Nehéz

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


It controls the fan’s operation
It is used to detect leaks
It monitors the liquid level in the tank or separator
It regulates the condensation temperature

260

Nehéz

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

Nehéz

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


Because NH₃ does not mix with most compressor oils
To increase the amount of refrigerant
To reduce the pressure
Because the oil mixes only with water

262

Nehéz

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

Nehéz

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


Glycol system
Indirect system
Thermosiphon system
Direct expansion (DX) system

264

Nehéz

What is the characteristic feature of a flooded evaporator system?


No level control is required
The evaporator is filled exclusively with vapour
The evaporator contains a large amount of liquid, which improves heat transfer
No separator is used

265

Nehéz

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, NH₃ cools an intermediate medium (e.g. glycol), which in turn cools the load
In an indirect system, no compressor is used

266

Közepes

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


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.
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.

267

Közepes

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 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).
The test pressure (maximum) is 30 bar.

268

Közepes

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


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.
The test must be carried out at all points on the refrigeration unit where there is a potential risk of refrigerant leakage.
The check should only be carried out at the connection points for measuring instruments (pressure switches, pressure gauges, temperature sensors).

269

Közepes

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


The device in question is perfectly leak-tight when we have carried out a check using a permanently installed electronic detector.
A device can be considered perfectly leak-tight if gas bubbles appear when it is submerged in water.
A given device can be considered perfectly leak-tight when the pressure drop during the test does not exceed 0.1 bar.
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

Közepes

What does EU Regulation 1516/2007 cover?


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 sets out health and safety requirements for soldering work.
The Regulation addresses the disposal of gases that contribute to the greenhouse effect.
The Regulation sets out requirements relating to brazing of refrigeration systems.

271

Nehéz

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


Connections on the condenser, as there is high pressure and the refrigerant is in liquid form
Compressor connections, 2. connections on the liquid refrigerant tank
Fittings, 2. valves, 3. seals, 4. parts/components exposed to vibration, 5. connections at safety devices.
Only compressor connections, as these are subject to vibration.

272

Könnyű

What is superheat?


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

273

Nehéz

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


We distinguish between direct and indirect methods of leak detection.
We distinguish between quality control methods for supplied materials and electronic testing methods.
We distinguish between methods for quality control of supplied materials and leak testing methods that do not involve quality control of supplied materials.
We distinguish between physical and chemical methods.

274

Nehéz

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


The check may be carried out by a specialist in leak testing.
The inspection may be carried out by a person employed and appointed by the owner of the installation.
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 check may only be carried out by a person who has previously carried out such a check.

275

Nehéz

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 having the appropriate technical resources, the relevant materials supplied, and suitable safety goggles.
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).
A prerequisite for carrying out a leak test using UV is that such a test is technically feasible.
A prerequisite for carrying out the inspection is holding the relevant authorisation for pressure testing issued by the UDT.

276

Nehéz

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


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 following the creation of a vacuum and leak detection 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

Nehéz

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


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.
This method is based on electronic leak detection.
It utilises pressure and temperature measurements, as well as an ultrasonic method.

278

Közepes

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


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
We increase the pressure as quickly as possible.
We increase the pressure at a rate of 10 bar/s.
We increase the pressure in any way.

279

Közepes

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


Only with devices fitted with hot cathodes.
Only with devices fitted with an infrared detector.
Only using devices with verified measurement sensitivity.
Only with devices fitted with an ‘Ion Pump’ sensor.

280

Közepes

What documentation should be checked before starting a leak test?


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).
Check the operating instructions for the machine/equipment.

281

Közepes

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


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 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 number of locations where leaks have occurred and the date of the inspection.
The date of the inspection, a record of the occurrence of the leak, and a signature.

282

Közepes

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


The pressure for the leak test is 2–3 bar.
The pressure value for the leak test is 10–12 bar.
At the discretion of the person authorised to carry out the pressure test.
Use a pressure not exceeding the maximum permissible pressure for the system (PS).

283

Közepes

What is temperature slip?


A specific temperature corresponds to a given vapour pressure.
It involves a decrease in temperature.
It involves an increase in temperature.
A specific temperature cannot be assigned to a given vapour pressure. There is a temperature difference between the start and end of evaporation.

284

Nehéz

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.
With the vacuum pump switched on, check whether the pressure in the system rises as a result of a leak.
After switching off the vacuum pump, we check whether the pressure in the system rises
If the pressure in the refrigeration system were to rise, we switch on the vacuum pump as required.

285

Nehéz

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


Only when servicing the unit.
Once every six months.
On initial commissioning.
At least once every 12 months.

286

Nehéz

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


Only when servicing the unit.
At least once every 12 months.
On initial commissioning.
Once every six months.

287

Közepes

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


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

288

Nehéz

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


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.
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.

289

Nehéz

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.
Visual leak inspection.
Leak testing using a fluorescent dye.
Measuring leaks using a handheld leak detector.

290

Nehéz

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


5 g/year.
10 g/year.
3 g/year.
8 g/year.

291

Közepes

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.
Category E only.
Only categories A1 and A2.
Categories D and E.

292

Nehéz

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 any time.
At the next periodic inspection.
Immediately after the repair.
Between 24 hours and 1 month after the repair.

293

Nehéz

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 every 6 months.
Once every 3 months.
Once every 12 months.
Once a month.

294

Közepes

Why is it advisable to subcool the liquid refrigerant?


This is advisable because it allows a smaller expansion valve to be used (less superheat at the valve).
This is advisable because it ensures that the liquid refrigerant, free of vapour bubbles, enters the expansion valve.
This is advisable because it allows a smaller condenser to be used (smaller heat exchange surface area).
This is advisable because it allows a smaller evaporator to be used (lower refrigerant temperature at the evaporator inlet).

295

Közepes

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

296

Közepes

Recovery of fluorinated greenhouse gases means:


The reprocessing of fluorinated greenhouse gases to achieve their specified standard properties.
The collection and storage of fluorinated greenhouse gases originating, for example, from machinery, equipment and containers.
The final decommissioning and withdrawal from service or use of a product or piece of equipment containing fluorinated greenhouse gases.
The reuse of fluorinated greenhouse gases following a basic purification process.

297

Közepes

Who is authorised to recover refrigerant from stationary refrigeration equipment:


The administrator of the operator’s account.
The operator.
A service technician holding an F-gas certificate in the relevant category.
The owner of the installation.

298

Közepes

Recovered refrigerants must be stored:


In any used refrigerant cylinder.
In any pressure vessel that has been officially certified.
In a specially adapted and labelled cylinder fitted with a two-way valve.
In a cylinder that previously contained the same type of refrigerant.

299

Közepes

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


Before each leak test of the equipment.
Only prior to the final disposal of equipment.
Always during servicing and maintenance of equipment.
Before the final disposal of equipment and, where applicable, during its servicing and maintenance.

300

Közepes

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


Add a special contaminant neutraliser to the mixture.
Such a mixture must be handed over to a specialist authorised company for regeneration or disposal.
You should attempt to purify the mixture yourself using a dehydrating filter.
Purify the mixture by passing it through a particulate filter and reuse it.

301

Közepes

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.
You should attempt to separate the mixture into its individual components.
Send this mixture to a specialist authorised company to have it neutralised.
Add a special refrigerant to the mixture.

302

Közepes

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


This involves the refrigerant being alternately drawn from the suction side and then from the discharge side of the refrigeration unit (compressor).
This involves using a suction device (compressor) to ensure that the refrigerant, in liquid form, is transferred into the cylinder.
This involves injecting nitrogen from the cylinder into the unit and expelling the liquid refrigerant from the unit.
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.

303

Közepes

What are the methods for managing waste refrigerant?


Recovery, disposal.
Recycling, regeneration, disposal.
Disposal, storage.
Regeneration, recovery.

304

Közepes

The most advantageous method of managing waste refrigerant is:


Disposal.
Regeneration.
Recycling.
Storage.

305

Közepes

The lower the evaporation temperature, ...


...the lower the refrigerant density, and the greater the cooling capacity of the compressor.
...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 lower the mass flow rate of the refrigerant.
...the greater the density of the refrigerant and the mass flow rate of the flowing refrigerant.

306

Közepes

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


It is irrelevant how pressure vessels should be marked.
They should bear only markings relating to weight and capacity.
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

Közepes

The recovery of refrigerants does not require the use of:


An electronic leak detector.
Hoses with shut-off valves.
Scales with a measurement range suitable for the size of the cylinder being filled.
A refrigerant recovery station.

308

Közepes

What functions does the compressor perform in a refrigeration system?


The compressor condenses the refrigerant.
The compressor creates a vacuum on the suction side of the system
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

Könnyű

What is the compressor’s compression ratio?


It is the ratio of the discharge pressure to the suction pressure of the compressor (pk/po).
It is the ratio of the suction pressure to the discharge pressure of the compressor (po/pk).
It is the ratio of the discharge pressure to the effective capacity of the compressor (p/Vk).
It is the amount of refrigerant that will be compressed in a single compressor cycle relative to the heat capacity.

310

Közepes

What is compressor flooding?


Flooding of the compressor due to rainfall.
A large amount of liquid refrigerant in the evaporator.
Flooding the compression chamber with liquid refrigerant or oil.
Suction of liquid refrigerant into the compressor’s suction line.

311

Közepes

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


From approximately 30% to 90% of 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.
Regulating the compressor motor speed is not the same as regulating the cooling capacity.

312

Könnyű

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

313

Közepes

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


Because the motor speed would decrease, and consequently the compressor’s capacity.
Because changing the phase sequence would reverse the direction of rotation of the compressor rotors, which could result in damage to the compressors.
Because these types of compressors are sensitive to voltage drops.
Because this type of compressor has difficulty starting up if the phase sequence is changed.

314

Közepes

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 8.
a compression ratio of less than 18.
a compression ratio greater than 8.

315

Közepes

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


Because it ensures the bearing remains lubricated.
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 protects the compressor’s crankshaft bearing.

316

Közepes

When is the refrigerant sufficiently cooled?


When the evaporator is covered in frost.
When no vapour bubbles are observed forming in the liquid sight glass.
When the liquid distributors are warm.
When the outlet from the condenser is cold.

317

Közepes

Why should the compressor crankcase be heated?


Heating improves the dissolution of the refrigerant in the oil, which is beneficial for its viscosity.
Heating keeps the lubricating oil in a liquid state.
Heating ensures that the lubricating oil is de-watered.
Heating prevents the refrigerant from dissolving in the oil.

318

Könnyű

What is the dead volume of a compressor?


This is the space between the bottom of the piston and the crankshaft cover.
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.
It is the space between the valve plate and the top of the piston.

319

Közepes

What are compressor sets?


These are sets comprising several compressors connected in any configuration.
These are units consisting of two-stage compressors.
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.

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What are the advantages of compressor units?


The ability to adjust the cooling capacity as required.
These are inexpensive and easy-to-install units.
Easy modification of the system.
Space-saving and lower energy consumption.

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


By this term, we mean the following parameters: compressor capacity, type of refrigerant, and the compressor’s geometric dimensions.
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 that the compressor’s application range is determined by the evaporation temperature ‘to’ at a given ambient temperature.
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.

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What are the basic functions of oil in a compressor?


The oil seals the gap between the piston and the cylinder.
The oil seals any leaks that develop in the system.
The oil absorbs moisture from the refrigerant that enters the compressor.
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.

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


By changing the compressor’s displacement, by varying the rotational speed, or by deactivating individual cylinders.
By partially covering the evaporator to reduce the heat exchange surface area.
By means of pressure control valves.
Using an expansion valve.

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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.

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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.

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How does a scroll compressor work?


It is a type of piston-type device.
A scroll compressor is also known as a turbo compressor.
It uses two screws to compress the refrigerant.
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.

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What physical process takes place in the evaporator?


The liquid refrigerant evaporates and a small amount of it becomes superheated.
It cools the refrigerant flowing through it.
It causes the refrigerant flowing through it to condense.
The medium flowing through the evaporator (glycol, water) evaporates, whilst the refrigerant condenses.

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


It ensures adequate lubrication of the compressor.
Capacity control protects the compressor from low thermal loads.
It ensures that the cooling capacity is adjusted based on condensing temperatures.
It allows the cooling capacity to be adjusted to meet requirements.

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Why is inverter speed control suitable for refrigeration compressors?


By reducing the speed of the refrigeration compressor motor, inverter speed control improves the return oil flow to the compressor.
Inverter speed control can be used with any type of compressor to ensure adequate lubrication.
Inverter speed control reduces energy consumption only under natural conditions.
Inverter speed control enables continuous, smooth regulation of cooling capacity.

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


It does, but only for reciprocating compressors.
Temperature has no effect on the compressor’s cooling capacity.
It does, but only if the gas is deeply cooled.
It has a significant effect on performance.

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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.
No.
Only screw compressors.
Only scroll compressors.

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


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

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


Water or air.
Air and CO2.
Ammonia
Water and an antifreeze mixture.

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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.
The heat absorbed in the evaporator is then released into the environment via the condenser
Heat from the compressor is then released into the environment via the condenser.
Heat released in the regenerative heat exchanger is absorbed by the condenser.

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


will always occur regardless of the temperature.
will occur provided a specially designed condenser is used.
will not occur.
temperature has no effect on condensation.

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


Subcooling using high-pressure hot vapour.
Subcooling of the liquid refrigerant in the final section of the condenser.
Subcooling using an additional heat exchanger and liquid nitrogen.
Subcooling of the refrigerant using oil (dissolving the refrigerant in oil).

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What is the purpose of controlling the condenser fan speed?


Condenser fan speed control reduces energy efficiency.
Condenser fan speed control ensures that the condensing pressure is maintained at the correct level.
Dispersion of the refrigerant in the event of a system leak.
Condenser fan speed control safeguards against the maximum permissible condensing pressure.