Tesztek

F-Gas English Low GWP

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

1

Közepes

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


The refrigerant absorbs heat from the surroundings and evaporates
The secondary fluid (glycol, water) condenses while the refrigerant evaporates
Hot vapour discharged by the compressor is desuperheated, condensed, and the resulting liquid is slightly subcooled
The refrigerant rejects only the heat generated in the compressor

2

Közepes

What mainly determines the condensing temperature of an air-cooled condenser?


The superheat
The evaporating temperature
The compressor discharge temperature
The ambient (inlet) air temperature

3

Közepes

Why does heat flow from the condenser to the surroundings?


Because HFC refrigerants attract heat from the surroundings
Because the condensing temperature is higher than the ambient temperature, and heat flows spontaneously from a warmer to a colder body (second law of thermodynamics)
Because the pressure in the condenser is lower than ambient
Because the compressor pushes heat directly into the surroundings

4

Közepes

What should you mainly pay attention to when operating a condenser?


That the outlet air temperature is higher than the condensing temperature
The colour of the condenser casing
That the inlet air temperature is lower than the outlet air temperature
Its general condition and the cleanliness of the heat-exchange surfaces

5

Közepes

What criteria should be considered when selecting a suitable condenser?


Only own experience and the dimensions
Fan noise, connection diameters and colour
Only the size and number of fans
The required capacity of the condenser and the technical specifications declared by the manufacturer

6

Közepes

How do contaminants (dust, particulates, deposits) affect the performance and efficiency of heat exchange surfaces in condensers?


Contaminants restrict heat transfer (reducing the heat transfer coefficient) and cause a reduction in condensing pressure.
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.
Contaminants do not significantly affect the efficiency and effectiveness of the heat exchange surfaces in condensers.
Contaminants increase the heat transfer area and reduce the condensing pressure.

7

Közepes

How does the capacity of an air-cooled condenser change when it becomes dirty?


It remains unchanged
It decreases
It increases
It increases because the fan speed rises

8

Közepes

What is the main consequence of heavy frost on an air-cooling evaporator?


An increase in condenser subcooling
Reduced heat transfer and airflow, resulting in a drop in cooling capacity and evaporating temperature
A rise in evaporating pressure
A rise in the cooled-air temperature with no effect on capacity

9

Közepes

What happens when the evaporation temperature drops?


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

10

Közepes

When is natural (off-cycle, air) defrosting possible?


Only in freezer rooms below −18 °C
When the air passing through the cooler is above 0 °C
Only in coolers fitted with speed-controlled fans
Never – electric heaters must be used in every air cooler

11

Közepes

When does frost form on the surface of an air-cooling evaporator?


Only when the system runs continuously
Always, in every air cooler
When the evaporator surface temperature is below 0 °C and below the dew point of the air
Only when the room air temperature falls below 0 °C

12

Közepes

In extensive pipework systems, flash gas (secondary evaporation) in the liquid line can be prevented by…


…using smaller-diameter pipes
…insulating the discharge line between the compressor and the condenser
…increasing the length of the liquid line
…additional subcooling of the liquid

13

Közepes

How does hot gas defrosting of the evaporator work?


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

14

Közepes

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


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

15

Közepes

What condition must electric heaters for evaporator defrosting meet?


They must be in direct contact with the refrigerant
Heat from the heaters must be carried by the running fans
They must be located beneath the evaporator
They must have good thermal contact with the heat-exchange surface (e.g. inserted in the fin block)

16

Közepes

Refrigerant distributor:


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

17

Közepes

What defrosting methods are used for air coolers?


Electric, hot gas, water spray and natural (at positive temperatures)
Natural only – other methods are ineffective and uneconomic
Only by switching off the fans with the compressor running
Electric only – other methods are not permitted in refrigeration

18

Közepes

The boiling point of a liquid rises when the pressure above the liquid…


…rises
…varies depending on the ambient temperature
…falls
…remains constant

19

Közepes

MOP in thermostatic expansion valves stands for:


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

20

Közepes

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


to adjust the evaporating pressure in the condenser
to meter refrigerant into the evaporator according to the superheat of the vapour leaving the evaporator
to maintain a constant condensing pressure
to maintain a constant compressor suction pressure

21

Közepes

What type of compressor motor can be used with a capillary tube?


A low-speed motor
An electronically commutated motor
A low-starting-torque motor (pressures equalise during standstill)
A high-starting-torque motor must be used

22

Közepes

What does a thermostatic expansion valve control?


The mass flow of refrigerant fed into the evaporator
The condensing pressure
The temperature in the cold room
The discharge temperature

23

Közepes

What does the manufacturer state as the factory setting of a thermostatic expansion valve?


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

24

Közepes

Where is a new or repaired system with an expansion valve and liquid receiver charged?


Anywhere – the charging point does not matter
In the liquid phase on the high-pressure side, with the compressor stopped
In the liquid phase into the compressor suction, with the compressor running
Through the capillary tube outlet during normal system operation

25

Közepes

What does a thermostatic or electronic expansion valve control?


Subcooling, by adjusting condensing pressure
The compressor speed
The evaporating pressure – closing below the set point
The amount of refrigerant fed to the evaporator according to superheat

26

Közepes

What does the MOP function of thermostatic expansion valves mean?


The valve maintains a constant condensing pressure
The valve limits subcooling
The valve prevents motor overheating by injecting liquid into the compressor
The valve limits the maximum evaporating (suction) pressure, protecting the compressor motor from overload, e.g. after defrost

27

Közepes

The lower the liquid temperature upstream of the expansion valve, (at the same mass flow)…


…the lower qo, with Qo unchanged
…the lower qo and the lower energy efficiency
…the lower qo and the lower Qo
…the higher the specific refrigerating effect qo [kJ/kg] and the higher the cooling capacity Qo

28

Közepes

How should the MOP point of an expansion valve be selected relative to the highest normal evaporating temperature?


Freely – the MOP value is irrelevant
Higher by approx. 20 K
A few kelvin higher (approximately 7 K)
About 7 K lower than that temperature

29

Közepes

What is the function of the suction pressure regulator?


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

30

Közepes

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


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.
To maintain the condensing pressure at the highest possible level.

31

Közepes

The use of a refrigerant distributor requires a thermostatic expansion valve ...


... with external pressure equalisation.
... with internal pressure equalisation.
... with an adsorption-type sensor filling.
... with a MOP function.

32

Közepes

What properties should good insulation materials have?


Low thermal conductivity (and low water absorption, vapour tightness)
An antistatic coating
The ability to absorb large amounts of moisture
High thermal conductivity

33

Közepes

When is refrigerant vapour superheated?


When the evaporating temperature is lower than the ambient temperature
When the pressure on the discharge side is higher than on the suction side
When the compressor motor temperature rises excessively
When its temperature is higher than the saturation temperature corresponding to its pressure

34

Közepes

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


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

35

Közepes

Where does the liquid line run?


Between the evaporator and the compressor
Between the compressor and the condenser
From the condenser (liquid receiver) to the expansion valve
Between the evaporator and the suction-line heat exchanger

36

Közepes

What is the function of the liquid receiver in a refrigeration system?


To collect liquid refrigerant and excess oil
To act as a reserve when the required charge is unknown
To store refrigerant and compensate for changes in the circulating charge as the heat load varies
To further subcool the condensed refrigerant

37

Közepes

What is the purpose of the liquid receiver during service work?


It further subcools the refrigerant before the expansion valve
It allows pump-down and temporary storage of the refrigerant
It collects excess oil circulating in the system
It is a reserve when the installer does not know the required charge

38

Közepes

Where should the liquid receiver be installed?


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

39

Közepes

What is the function of the suction pressure regulator fitted to the suction pipe when the compressor starts up?


It opens when the suction pressure upstream of the compressor drops.
It regulates the evaporation pressure.
It regulates the condensing pressure.
It closes when the suction pressure upstream of the compressor drops.

40

Közepes

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


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

41

Közepes

Which refrigerants belong to the HFC group?


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

42

Közepes

Which refrigerants belong to the HFO group?


R22, R12.
R134a, R404A.
R134a, R290.
R1234yf, R1234ze(E).

43

Közepes

What are the characteristics of R410A refrigerant compared to R407C refrigerant?


The saturation pressure of both refrigerants is roughly the same.
The saturation pressure of R407C refrigerant is much higher than that of R410A.
The saturation pressure of R407C is 150% higher than that of R410A.
The saturation pressure of R410A refrigerant is higher than that of R407C.

44

Közepes

What does the TEWI indicator define?


The global warming potential of a gas relative to CO₂ over a 100-year horizon
The ability of the ozone layer to recover
Total Equivalent Warming Impact: the sum of direct emissions (leakage and refrigerant losses at disposal) and indirect emissions (CO₂ from generating the energy consumed by the equipment) over its lifetime
The impact of a refrigerant on the ozone layer

45

Közepes

What are the characteristics of R452A compared with R404A?


It is a non-flammable (A1) HFC/HFO blend with properties similar to R404A and a GWP about 45% lower
It is a flammable and toxic single-component HFC
The temperature glide of R452A is half that of R404A
Both are azeotropic and have no temperature glide

46

Közepes

What distinguishes R1234yf from R134a?


A higher normal boiling point
A higher critical temperature
It is mildly flammable (class A2L), whereas R134a is non-flammable (A1)
Higher toxicity

47

Közepes

How does CO₂ (R744) compare with R134a?


It has identical properties and is a drop-in replacement for R134a
Unlike R134a, it is an azeotropic mixture
Its temperature glide is 7 K greater than that of R134a
It has a lower critical temperature, much higher operating pressures and a much higher volumetric cooling capacity (smaller compressors and pipes)

48

Közepes

Which of the following is NOT a fluorinated greenhouse gas?


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

49

Közepes

What is the greenhouse effect?


Chlorine compounds destroy stratospheric ozone, increasing UV radiation at the surface
Clouds reflect ultraviolet radiation, which makes the air near the surface warmer
Greenhouse gases absorb and re-emit the Earth's infrared radiation, warming the lower atmosphere
Dust in the atmosphere reflects sunlight, lowering the average surface temperature

50

Közepes

What is R1270?


Propane
Isobutane
n-Butane
Propene (propylene)

51

Közepes

How do refrigeration systems contribute to the greenhouse effect?


Only through the heat rejected by the condenser
Indirectly (through energy consumption) and directly (through emissions of refrigerant into the atmosphere)
Only through CO₂ given off by the compressor motor
Through oil emitted into the atmosphere from the condenser and filter

52

Közepes

What is the greenhouse effect?


The absorption of solar radiation by the Earth's surface
The trapping of heat in the Earth's atmosphere, which hinders the radiation of heat into space
The formation of a layer that traps only heat from fuel combustion in aircraft
The filtering of solar radiation by the atmosphere

53

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) 2015/1188
Regulation (EU) No 517/2014
Regulation (EU) 2024/573

54

Közepes

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


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

55

Közepes

What are the ecodesign obligations of manufacturers of refrigerating appliances?


Meeting implementing regulations (e.g. 2019/2019, 2015/1095): efficiency, spare parts, reparability
Only using energy labels under Regulation (EU) 2024/573
Only declaring F-gas quantities under Regulation (EU) No 517/2014
Only implementing an ISO 9001 quality management system

56

Közepes

What is the main objective of EU ecodesign legislation (Directive 2009/125/EC, now Regulation (EU) 2024/1781 – ESPR)?


To facilitate imports from outside the EU
To reduce the negative environmental impact of products by improving energy efficiency, durability and recyclability
To increase sales of electrical appliances in the EU
To standardise the appearance of products in the EU

57

Közepes

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


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

58

Közepes

How do certain gases contribute to the greenhouse effect?


They limit UV radiation reaching the Earth's surface, changing the heat balance
They deplete the ozone layer, so more solar radiation reaches the surface
They trap thermal radiation that the Earth would otherwise emit into space
They heat the air through chemical reactions with atmospheric oxygen and nitrogen

59

Közepes

What is the purpose of a sight glass (with moisture indicator)?


Visual assessment of the refrigerant condition in the liquid line (bubbles) and of system moisture
Regulating compressor pressure
Measuring condenser temperature
Emergency shut-off of flow

60

Közepes

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


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

61

Közepes

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


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

62

Közepes

What is the function of the liquid receiver in relation to system tightness?


It keeps the whole system at constant pressure regardless of load
It regulates the oil returning to the compressor
It controls the evaporating temperature by varying the circulating charge
It stores refrigerant; checking its liquid level helps detect charge loss

63

Közepes

What is the role of a gauge manifold with thermometers (temperature probes)?


It measures pressures and temperatures to determine superheat and subcooling and thus assess the system charge (indirect leak check)
It monitors refrigerant moisture content
It relieves pressure if it is exceeded
It controls oil level

64

Közepes

What is the role of defrost controls?


They monitor the moisture content of the refrigerant
They control compressor discharge pressure during defrost
They drain excess oil from the evaporator to the receiver
They protect the evaporator from icing and damage that could lead to leaks

65

Közepes

Where can the lists of fluorinated greenhouse gases be found?


In a regulation of the Minister of Economy on the list of fluorinated greenhouse gases
In Annexes I–III to Regulation (EU) 2024/573 of the European Parliament and of the Council
In the Vienna Convention for the Protection of the Ozone Layer
In the national Act on ozone-depleting substances and certain fluorinated greenhouse gases

66

Közepes

Where can the lists of ozone-depleting substances be found?


In Annexes I and II to Regulation (EU) 2024/590 of the European Parliament and of the Council
In the Vienna Convention for the Protection of the Ozone Layer
In a regulation of the Minister of the Environment on the list of controlled substances
In the national Act on ozone-depleting substances and certain fluorinated greenhouse gases

67

Közepes

Why is ammonia (R717) classed as a toxic refrigerant?


Because it is colourless and odourless and therefore hard to detect
Because it does not react with water, making neutralisation difficult
Because it is heavier than air and displaces oxygen
It severely irritates the respiratory tract, eyes and skin, and is poisonous when inhaled at higher concentrations

68

Közepes

Where and by when must entities obliged under the Polish Act of 15 May 2015 submit annual reports on ODS and F-gases?


By 31 January, in the Central Register of Operators (CRO)
By 31 March, electronically to the Ministry of Climate and Environment
By the end of the calendar year, on a form at a regional office of the Office of Technical Inspection (UDT)
By 28 February of the following year, electronically via the Reports Database (BDS) run at the Institute of Industrial Chemistry (ICHP)

69

Közepes

Which installation measure has a major impact on compressor energy efficiency?


Installing a suction line smaller than recommended
Omitting the filter-drier to reduce flow resistance
Proper evacuation and dehydration of the system (removing air and moisture)
Charging extra refrigerant 'as a reserve' above the nameplate value

70

Közepes

How does regular oil-level monitoring affect compressor operation?


It increases cooling capacity above nominal
It allows any type of oil to be topped up
It ensures proper lubrication and limits wear and energy losses
It allows the crankcase heater to be omitted

71

Közepes

Regulation (EU) 2024/590 relates to:


Ozone-depleting substances
Conditions for F-gas certification of companies recovering and reclaiming refrigerants
Health and safety during refrigerant recovery
Alternative refrigerants replacing fluorinated greenhouse gases

72

Közepes

What is the significance of proper suction and discharge pressure control?


The lowest possible suction pressure is best
The highest possible condensing pressure is best
It keeps the compressor at optimal conditions (suction pressure as high and condensing pressure as low as permissible)
Pressures do not affect energy use

73

Közepes

Which maintenance measure reduces compressor energy consumption?


Raising the high-pressure switch setting
Replacing the filter-drier when the pressure drop or moisture indicator shows it is necessary
Permanently disabling the crankcase heater
Topping up refrigerant at every service visit

74

Közepes

How does air (non-condensable gas) in the system affect operation?


It lowers the condensing pressure
It improves condenser heat transfer
It raises the condensing pressure and reduces efficiency
It only affects the sight-glass indication

75

Közepes

What role do controls play in compressor efficiency?


They matter only in NH₃ systems
They increase the circulating refrigerant charge
They provide safety only, with no energy effect
They enable optimised operation and lower energy use (e.g. floating head pressure, capacity matching)

76

Közepes

How does suction superheat at the compressor affect efficiency?


Excessive superheat reduces efficiency and raises the discharge temperature
The higher the superheat, the higher the efficiency
Superheat has no effect
Zero suction superheat is optimal

77

Közepes

How does correct system layout affect efficiency?


It affects only appearance
It shortens pipe runs and limits pressure drops and energy losses
Longer pipes improve subcooling and always increase efficiency
It doesn't matter

78

Közepes

How important is suction pipe insulation?


It is needed only for appearance
It increases energy consumption
It has no effect
It limits heat gain and excessive superheat, improving efficiency

79

Közepes

Which measure most improves condenser energy efficiency?


Regular cleaning of heat-exchange surfaces
Increasing the refrigerant charge
Raising the condensing pressure set point
Reducing fan speed to the minimum

80

Közepes

Which refrigerants damage the ozone layer?


All refrigerants containing chlorine or bromine in their molecules
All natural refrigerants
All refrigerants containing fluorine and hydrogen in their molecules
All refrigerants containing carbon in their molecules

81

Közepes

How does correct condensing pressure control affect efficiency?


It is best to keep a constant high condensing pressure all year
It has no effect
It always increases energy use
It keeps the lowest pressure that still ensures proper expansion-valve feed, reducing energy use

82

Közepes

How does insulation of heating and DHW pipework affect the efficiency of a heat pump system?


It impairs cooling
It increases pressure
It doesn't matter
It reduces energy losses and improves overall system efficiency

83

Közepes

Which measure most improves the energy efficiency of an air-cooling evaporator?


Restricting the airflow through the evaporator
Increasing the refrigerant charge above nominal
Raising the condensing temperature by a few kelvin
Defrosting at the right time and keeping the fins clean

84

Közepes

What does a Certificate A2 for natural persons (Implementing Regulation (EU) 2024/2215) authorise?


Only leak checks that do not entail breaking into the refrigerant circuit
Only recovery of F-gases from equipment containing less than 3 kg (or 6 kg in hermetically sealed systems)
All activities (leak checks, installation, repair, maintenance, servicing, decommissioning, recovery) involving F-gases and hydrocarbons in equipment containing less than 3 kg, or less than 6 kg in labelled hermetically sealed systems
All activities involving equipment using CO₂ (R744)

85

Közepes

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


It increases operational safety
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

86

Közepes

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


Only requirements for periodic leak checks of refrigeration equipment
Design requirements and conformity assessment for pressure equipment
Health and safety requirements for brazing and welding on refrigeration installations
Limiting emissions, use and marketing of F-gases, HFC phase-down, certification and reporting

87

Közepes

What is the main design difference in hydrocarbon refrigeration systems?


Lower energy efficiency
Higher operating pressures
The need to eliminate ignition sources and limit the charge because of the refrigerant's flammability
No need for safety measures

88

Közepes

How do compressors used in hydrocarbon systems differ?


There is no difference
They need no lubrication
They must be approved by the manufacturer for the specific flammable refrigerant (e.g. electrical components that are not ignition sources, suitable oil)
They must operate at higher pressures than HFC compressors

89

Közepes

How can you tell that the system has been overcharged with refrigerant?


It cannot be checked, because the sight glass is not intended for this
The compressor runs at a lower load and the suction pressure drops
Even under a very small heat load, frost forms on the suction line
Under normal operating conditions the condensing pressure and subcooling rise markedly because excess liquid floods the condenser and reduces its active surface

90

Közepes

Before charging the unit with refrigerant, it is essential to…


…carry out a tightness test (and evacuate the system)
…fill in the unit's data sheet
…check the compressor suction and discharge connections
…carry out a trial start-up

91

Közepes

What information must appear on the label of equipment containing F-gases?


The weight and capacity of the pipework and the colour code of the casing paint
That it contains an F-gas, its designation, quantity in kg and t CO₂ eq, and GWP
Only the trade name of the refrigerant and the unit's serial number
The manufacturer's logo, the unit weight and year of manufacture from the rating plate

92

Közepes

Which set of information best reflects the content of the equipment records required by Regulation (EU) 2024/573?


Only the date of installation and the installer's name
The owner, installer and service technician of the unit
Operator details, equipment details, type and quantity of refrigerant, and information on servicing and repairs
The make and model of the unit

93

Közepes

Who is responsible for keeping the equipment records?


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

94

Közepes

Where are oil traps installed on the suction line?


Before the safety valve on the suction side
At the bottom of vertical suction risers with upward flow
Immediately before the compressor suction connection
At the inlet to every component of the refrigeration system

95

Közepes

Which symptoms with the compressor running indicate a refrigerant leak (undercharge)?


Rising liquid level in the receiver and increasing subcooling
Rising condensing and suction pressures with no superheat
Low suction pressure, high superheat and negligible subcooling
Sight glass full of liquid and rising oil level in the crankcase

96

Közepes

Which components of a refrigeration system are potential leak points subject to leak checks?


Only high-pressure-side components
Joints, valves (including stems), seals (including those on replaceable filters and driers), parts subject to vibration and connections to safety and measuring devices
Hermetic compressors, liquid receivers and liquid separators
Only suction-side components

97

Közepes

What pressure is used for the pressure tightness test of an installation?


The pressure specified in EN 378-2 or by the manufacturer, not exceeding the maximum allowable pressure of the system (PS)
Always 30 bar
A pressure equal to the maximum pressure measured during operation
A pressure chosen by the technician based on experience

98

Közepes

At which points of the unit must the leak check be carried out?


Only on discharge-side components
Only on compressor shut-off valves, solenoid valves and filters
At all points where there is a potential risk of refrigerant leakage
Only at connections of measuring instruments

99

Közepes

When can a unit be considered tight after a pressure test?


When it has been checked with a fixed electronic detector
When the pressure drop does not exceed 0.1 bar regardless of the test duration
When gas bubbles appear after immersion in water
When the pressure remains constant during the test (allowing for temperature-related changes); any unexplained pressure drop requires the leak to be located

100

Közepes

Which legal act currently sets out the obligation to check stationary refrigeration equipment containing F-gases for leaks, and how often this must be done?


Commission Regulation (EC) No 1516/2007
Implementing Regulation (EU) 2024/2215
Regulation (EU) No 517/2014
Regulation (EU) 2024/573

101

Közepes

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


Gradually, in stages, checking for leaks at each level until the test pressure is reached
In one step, by fully opening the nitrogen cylinder valve
In any way
As quickly as possible

102

Közepes

What electronic equipment should be used for leak checking?


Only devices with an 'ion pump' sensor
Only hot-cathode devices
Only detectors with an infrared sensor
Detectors suited to the refrigerant in the system, with appropriate sensitivity, checked periodically

103

Közepes

What documentation should be checked before starting a leak check?


The operator's fixed-asset inventory ledger
Only the installation invoice and the first start-up report
Attendance sheets of the plant-room staff for the year
The equipment records – especially recurring problems and previous leaks

104

Közepes

What information must be recorded in the leak check report?


The date, a general note about the leak and the operator's signature
Date, number and location of leaks, how they were repaired, technician details and signature
The method used, the time spent on site and the cost of repair
Only the number of leaks found and the date of the check

105

Közepes

What pressure should be used for the pressure tightness test?


Always 2–3 bar
A pressure not exceeding the maximum allowable pressure of the system (PS)
Always 10–12 bar
Any pressure, at the technician's discretion

106

Közepes

What is the temperature glide of a refrigerant?


In zeotropic mixtures, the difference between the temperatures at the start and end of a phase change (boiling or condensation) at constant pressure
The temperature rise of the vapour in the compressor
The temperature drop of the refrigerant across the expansion valve
A property of single-component refrigerants, for which one saturation temperature corresponds to a given pressure

107

Közepes

In which equipment is a leakage detection system required?


Equipment with 50 t CO₂ eq or more of F-gases, regardless of equipment type
Equipment with 5 t CO₂ eq or more of F-gases, regardless of equipment type
Equipment with ≥ 500 t CO₂ eq of Annex I F-gases (or ≥ 100 kg of Annex II Section 1 gases)
Equipment with 30 kg or more of F-gases, regardless of their GWP

108

Közepes

What should you check before using a portable electronic leak detector?


That it suits the refrigerant and has been checked as the manufacturer requires
That it holds a valid UDT inspection certificate
That it has been zeroed close to the suspected leak point
That it has an infrared sensor, as only this type is permitted

109

Közepes

Which certificate types (A1, A2, B, C, D, E) authorise leak checks of equipment containing F-gases?


Only A1 and A2
All except D
Only E
A1, A2 and E

110

Közepes

Why is it advisable to subcool the liquid refrigerant?


To allow a smaller expansion valve to be used
To allow a condenser with a smaller heat-exchange surface to be used
To ensure that liquid free of vapour bubbles enters the expansion valve
To lower the evaporating temperature in the evaporator

111

Közepes

What must be done after repairing a leak in the refrigeration unit of a refrigerated trailer?


Issue the invoice and leave the leak check to the next periodic service
Visually inspect only the bolted and brazed joints near the repair
Update the equipment records and carry out a leak check (it may be done directly after repair)
Charge an alternative refrigerant, start up and measure the parameters

112

Közepes

Recovery of fluorinated greenhouse gases means:


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.
The collection and storage of fluorinated greenhouse gases from containers, products and equipment during maintenance or servicing or prior to their disposal.
The reprocessing of fluorinated greenhouse gases to achieve their specified standard properties.

113

Közepes

Who is authorised to recover refrigerant from stationary refrigeration equipment containing F-gases?


The administrator of the operator's account in the register
The owner of the installation
The operator
A natural person holding a certificate of the relevant type (A1; A2. or D within their charge limit)

114

Közepes

How must recovered refrigerants be stored?


In any pressure vessel that has some form of approval
In any used refrigerant cylinder, provided it is leak-tight
In a labelled recovery cylinder with a dual valve and a valid inspection
In a disposable (non-refillable) cylinder that held the same refrigerant

115

Közepes

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


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

116

Közepes

What should be done if recovered refrigerant is contaminated (e.g. with acid, air or moisture)?


Add a special contaminant neutraliser
Pass it through a particle filter and reuse it
Hand it over to a specialised, authorised company for reclamation or destruction
Clean the mixture yourself using a filter-drier

117

Közepes

What should be done if different refrigerants have been mixed in a storage cylinder?


Pass it through a filter-drier and reuse it
Add a special refrigerant to the mixture
Hand the mixture over to an authorised company – as a rule for destruction
Separate the mixture into its components yourself

118

Közepes

How does push-pull refrigerant recovery work?


The recovery unit draws vapour from the system and condenses it in the cylinder
The recovery unit draws vapour from the recovery cylinder and pushes it into the system; the pressure difference forces liquid refrigerant out of the system into the cylinder
Refrigerant is drawn alternately from the suction and discharge sides of the compressor
Nitrogen is injected into the system, pushing the refrigerant into the atmosphere

119

Közepes

What are the options for managing waste refrigerant?


Reclamation, recovery
Disposal, storage
Recycling, reclamation, destruction
Recovery, disposal

120

Közepes

Which management option restores recovered refrigerant to a quality equivalent to virgin product, so that it can be used by any undertaking?


Storage
Recycling
Reclamation
Destruction

121

Közepes

The lower the evaporating temperature, …


…the greater the density of the suction vapour and the lower the refrigerant mass flow rate
…the lower the density of the suction vapour and the lower the refrigerant mass flow rate
…the lower the density of the suction vapour and the greater the cooling capacity of the compressor
…the greater the density of the suction vapour and the greater the refrigerant mass flow rate

122

Közepes

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


With the manufacturer's logo and date of manufacture
The marking is optional
Among other things: the number of the design and testing standard, marks of the approving country and the inspection body, the date of the initial inspection, and the manufacturer's and operational marks
Only with weight and capacity marks

123

Közepes

The recovery of refrigerants does not require the use of:


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

124

Közepes

What functions does the compressor perform in a refrigeration system?


The compressor creates a vacuum on the suction side of the system
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.
The compressor compresses ambient air and increases the pressure of the refrigerant.
The compressor condenses the refrigerant.

125

Közepes

What is compressor flooding (liquid slugging)?


A large amount of liquid refrigerant in a flooded evaporator, which is a normal operating condition
Flooding of the compressor by rainwater
Liquid refrigerant or oil entering the compression chamber
Excess oil in the condenser

126

Közepes

Within what range is the compressor motor speed typically controlled using a frequency inverter?


From approximately 10% to 90% of nominal capacity
Speed control does not change the cooling capacity
Approximately 30 to 75 Hz, corresponding to about 60–150% of nominal capacity (depending on the compressor manufacturer)
By a maximum of 10%

127

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 this type of compressor has difficulty starting up if the phase sequence is changed.
Because these types of compressors are sensitive to voltage drops.

128

Közepes

What compression ratio should each stage of a two-stage vapour-compression system have (rule of thumb)?


Less than approximately 8
Greater than 18
Equal to 1
Greater than 10

129

Közepes

Why is a shaft seal necessary in open-type compressors?


To protect the crankshaft bearing
To prevent air from entering and refrigerant from leaking out of the compressor
To ensure the bearing remains lubricated
Only to prevent oil leakage

130

Közepes

How can you check whether the liquid refrigerant is sufficiently subcooled?


Check whether the liquid distributor upstream of the evaporator feels warm
Compare the liquid-line temperature with the saturation temperature at the measured condensing pressure
Check by touch whether the condenser outlet is noticeably colder than ambient
Check whether the whole evaporator surface is covered with an even layer of frost

131

Közepes

Why is the compressor crankcase heated?


To increase dissolution of refrigerant in the oil and improve its viscosity
To limit refrigerant migration into, and dissolution in, the oil during standstill
To dehydrate the oil
To keep the lubricating oil liquid

132

Közepes

What are compressor packs (racks)?


Sets of compressors connected in any configuration
Several air-cooled condensers
Several compressors connected in parallel on a common frame with common suction and discharge headers
Units with two-stage compressors

133

Közepes

What is the main advantage of multi-compressor packs?


A smaller refrigerant charge than a single-compressor system
Stepwise capacity matching to demand, plus redundancy
No need for compressor controls and safety devices
Low purchase cost and easy installation without special controls

134

Közepes

What is meant by the operating envelope (application range) of a compressor?


A range determined only by the evaporating temperature
A range determined by the evaporating temperature at a given ambient temperature
The permissible range of evaporating and condensing temperatures (to, tk), or the corresponding pressures, within which the compressor may operate
The capacity, refrigerant type and dimensions of the compressor

135

Közepes

What are the basic functions of oil in a compressor?


Sealing leaks that develop in the installation
Increasing the cooling capacity of the refrigerant
Lubricating bearings and sliding surfaces, removing heat, and sealing clearances (e.g. between piston and cylinder, or rotors)
Absorbing moisture from the refrigerant

136

Közepes

What are the most effective ways of controlling compressor cooling capacity?


Pressure control valves
Partially covering the evaporator
Changing the displacement: varying the rotational speed or unloading cylinders
An expansion valve

137

Közepes

What does hot-gas bypass capacity control involve?


High-pressure liquid is injected into the suction to increase capacity
Bypass is not used for capacity control
Part of the hot discharge gas is passed through a bypass valve to the suction side (or evaporator inlet), reducing the effective capacity
The compressor speed is varied

138

Közepes

What is the fundamental difference between hermetic and semi-hermetic compressors?


The semi-hermetic compressor has no motor inside the casing
Both can be dismantled; they differ only in cooling capacity
Semi-hermetic compressors run more quietly as a complete unit
The semi-hermetic casing is bolted (can be opened); the hermetic one is welded

139

Közepes

How does a scroll compressor work?


A scroll compressor is also known as a turbo compressor.
It is a type of piston-type device.
It is a positive-displacement compressor in which compression results from the interaction of a fixed and an orbiting scroll.
It uses two screws to compress the refrigerant.

140

Közepes

What physical process takes place in the evaporator?


The liquid refrigerant evaporates, absorbing heat, and the vapour is slightly superheated at the outlet
The refrigerant is subcooled as a liquid
The secondary fluid (glycol, water) evaporates while the refrigerant condenses
The refrigerant condenses

141

Közepes

What is the purpose of compressor capacity control?


To ensure compressor lubrication
To increase the condensing pressure
To match the cooling capacity to the current demand
To match capacity to the condensing temperature

142

Közepes

Why is inverter speed control advantageous for refrigeration compressors?


It can be used with any compressor to ensure lubrication
Reducing the speed improves oil return to the compressor
It enables continuous, smooth control of cooling capacity
It increases compressor capacity above nominal at any frequency

143

Közepes

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


Yes, but only in reciprocating compressors, not scroll
Yes – higher temperature lowers vapour density, mass flow and capacity
Yes, but only if the suction gas is deeply cooled
No – capacity depends only on the compressor displacement

144

Közepes

In the case of compressor units fitted with an oil level control system, is it necessary to install the compressors at the same height?


No.
Only screw compressors.
Only scroll compressors.
Yes.

145

Közepes

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


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.
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.

146

Közepes

Which media most commonly absorb heat from the refrigerant in the condenser?


Air and CO₂
Only a water–glycol mixture
Ammonia
Air or water

147

Közepes

What is the function of the condenser in refrigeration systems?


Releasing only the heat from the compressor into the surroundings
Absorption of heat rejected in the regenerative heat exchanger
Releasing to the environment the heat absorbed in the evaporator and the heat added during compression
Releasing only the heat absorbed in the evaporator into the surroundings

148

Közepes

If the refrigerant temperature on the high-pressure side is above its critical temperature, condensation…


…always occurs regardless of temperature
…does not depend on temperature
…does not occur
…occurs provided a special condenser is used

149

Közepes

How is liquid subcooling usually achieved in a refrigeration system?


With hot high-pressure vapour
In the final section of the condenser (or in an additional subcooler)
With an additional heat exchanger using liquid nitrogen
By dissolving the refrigerant in oil

150

Közepes

What is the purpose of condenser fan speed control?


Only to protect against exceeding the maximum condensing pressure
To disperse refrigerant in the event of a leak
To reduce energy efficiency
To keep the condensing pressure at the correct level

151

Közepes

Which international agreement introduced the global phase-down of HFC production and consumption?


The Vienna Convention for the Protection of the Ozone Layer
The Kyoto Protocol
The Kigali Amendment to the Montreal Protocol
The Paris Agreement

152

Közepes

Which international treaty governs the phase-out of ozone-depleting substances (CFCs, HCFCs)?


The Paris Agreement
The UN Framework Convention on Climate Change (UNFCCC)
The Stockholm Convention
The Montreal Protocol

153

Közepes

Can HFC refrigerant recovered during a repair be put straight back into the same equipment without any cleaning (filtering/drying)?


Yes, if the operator agrees
Yes, if less than 24 hours have passed
No – recovered F-gas may be used for filling only after it has been recycled or reclaimed
Yes, always

154

Közepes

Who may purchase HFCs for servicing refrigeration equipment?


Only the equipment operator
Any adult
Only a person holding the relevant certificate or an undertaking employing such persons
Any business

155

Közepes

Under what condition may non-hermetically sealed split air conditioning charged with F-gas be sold to an end user?


When the user signs a statement that they will install it themselves
Only if the unit contains less than 3 kg of refrigerant
Unconditionally
When evidence is provided that installation will be carried out by a certified undertaking

156

Közepes

By when must the holder of an F-gas certificate issued under Regulation (EU) No 517/2014 first complete refresher training or an evaluation process?


Never – the certificate is valid indefinitely
By 31 December 2030
By 12 March 2029 (and then at least every 7 years)
By 12 March 2025

157

Közepes

What must the holder of a Category I certificate (Regulation 2015/2067) do to continue using it?


Nothing – Category I automatically becomes A1
Update their knowledge to the level of Certificate E
Update their knowledge and skills to the level of Certificate A1 (Annex I to Regulation 2024/2215)
Apply for an extension without training

158

Közepes

What does Certificate C under Implementing Regulation (EU) 2024/2215 authorise?


All activities in relation to CO₂
Leak checks without breaking into the circuit
All activities in Article 2(1) in relation to ammonia (NH₃)
Recovery of F-gases from equipment <3 kg

159

Közepes

May a person enrolled in a certification training course carry out certified activities?


Yes – independently, for 6 months
Yes – with no time limit, if employed by a certified company
No, never
Yes – under the supervision of a certified person, for no more than 24 months in total

160

Közepes

How long must the operator keep the records of equipment subject to leak checks, if they are not kept in a national database?


At least 2 years
At least 1 year
At least 5 years
Until the equipment is decommissioned

161

Közepes

What distinguishes class 2L refrigerants from class 2?


A maximum burning velocity of no more than 10 cm/s
Heat of combustion above 19 MJ/kg
No lower flammability limit
Higher toxicity

162

Közepes

What is the lower flammability limit (LFL) of propane R290?


Approx. 0.38 kg/m³
Approx. 0.038 kg/m³ (approx. 2.1% by volume)
Approx. 1.8 kg/m³
Approx. 0.307 kg/m³

163

Közepes

Equipment marked 'Ex II 3G' may be used in zone:


0
2 (explosive gas atmosphere unlikely and short-lived)
1
20 (dusts)

164

Közepes

How is explosion hazard zone 2 defined?


An explosive atmosphere is present continuously or for long periods
An explosive atmosphere is not likely in normal operation and, if it occurs, persists only for a short period
An area where flammable refrigerants are never used
An explosive atmosphere is likely to occur in normal operation

165

Közepes

Under which UN number is propane (R290) carried under ADR?


UN 1005
UN 3252
UN 3337
UN 1978

166

Közepes

At what concentration should a portable flammable gas detector used for R290 work raise an alarm at the latest?


No higher than 25% of LFL
At 150% of LFL
At 100% of LFL
At 5% propane by volume

167

Közepes

How should a recovery cylinder be prepared before filling it with a hydrocarbon refrigerant?


No preparation is needed
Evacuate it (no air) and label it for the specific flammable refrigerant
Partly fill it with nitrogen to 5 bar
Purge it with compressed air

168

Közepes

What is the correct approach in a risk analysis before work on an HC system?


First select PPE, then possibly remove ignition sources
First eliminate hazard sources (e.g. ignition sources); where this is not possible, identify them and apply mitigating measures (ventilation, detection, PPE)
The risk analysis is done after the work is finished
Having a fire extinguisher is sufficient

169

Közepes

Which property of ammonia helps people detect a leak early?


A very low odour threshold (a few ppm)
It is yellow in air
It is denser than air
It is odourless

170

Közepes

What hazard does a large CO₂ leak in an enclosed room pose to people?


Explosion of the mixture with air
Formation of hydrogen fluoride
Accumulation near the floor and asphyxiating/toxic effects at high concentrations
CO₂ is completely safe

171

Közepes

What is floating head pressure and what does it achieve?


It increases subcooling by flooding the condenser
It keeps a constant high condensing pressure all year
It means switching condenser fans off periodically
It lets the condensing pressure fall with ambient temperature, reducing compressor work and raising COP (requires an expansion valve that works at a small pressure difference)

172

Közepes

How do SEER/SCOP differ from EER/COP?


EER/COP are always higher than SEER/SCOP
SEER/SCOP apply only to natural-refrigerant equipment
There is no difference – they are synonyms
SEER/SCOP are seasonal indicators accounting for part load and climate (EN 14825); EER/COP refer to a single operating point (EN 14511)

173

Közepes

Which design approach can significantly reduce the F-gas charge of a large refrigeration installation?


Larger liquid-line diameters
An indirect (secondary-coolant) system or a cascade with a natural refrigerant in the low stage, plus heat exchangers with small internal volume
Omitting pipe insulation
Adding a second liquid receiver

174

Közepes

Why must the charge of small, critically charged R290 systems be weighed to within a few grams during service?


Small charge deviations significantly change superheat/subcooling and efficiency, and overcharge increases the risk in a leak
Because R290 is more expensive than HFCs
Because scales are not needed – charging is done by sight glass
Because extra R290 improves efficiency

175

Közepes

Which information must be entered in the equipment records after a leak check?


Only the date of the check
Only the operator's signature
The date and result of the check and the identity of the undertaking and person who performed it (with certificate number)
Only the equipment's energy consumption

176

Közepes

What must be done when an indirect method (e.g. parameter analysis) indicates a possible leak?


Nothing – indirect methods are sufficient
Record it and check at the next periodic inspection
Carry out a direct-method examination to locate the leak
Top up the refrigerant and end the check