Tests

F-Gas English Low GWP

All questions
HFC | Flammable | CO₂ | NH₃
Easy questions | Medium questions | Difficult questions

1

Medium

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


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

2

Medium

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


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

3

Medium

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 compressor pushes heat directly into the surroundings
Because the pressure in the condenser is lower than ambient

4

Medium

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


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

5

Medium

What criteria should be considered when selecting a suitable condenser?


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

6

Medium

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 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.
Contaminants restrict heat transfer (reducing the heat transfer coefficient) and cause a reduction in condensing pressure.

7

Medium

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


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

8

Medium

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


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

9

Medium

What happens when the evaporation temperature drops?


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

10

Medium

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


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

11

Medium

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


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

12

Medium

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


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

13

Medium

How does hot gas defrosting of the evaporator work?


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

14

Medium

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


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

15

Medium

What condition must electric heaters for evaporator defrosting meet?


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

16

Medium

Refrigerant distributor:


ensures even distribution of the refrigerant to the individual sections of the condenser.
ensures an even distribution of the refrigerant to the individual sections of the evaporator.
ensures the even distribution of the refrigerant discharged by compressors connected in parallel.
acts as a buffer for the refrigerant in the event that the pressure upstream of the expansion valve is exceeded.

17

Medium

What defrosting methods are used for air coolers?


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

18

Medium

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


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

19

Medium

MOP in thermostatic expansion valves stands for:


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

20

Medium

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


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

21

Medium

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


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

22

Medium

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

Medium

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


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

24

Medium

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


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

25

Medium

What does a thermostatic or electronic expansion valve control?


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

26

Medium

What does the MOP function of thermostatic expansion valves mean?


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

27

Medium

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


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

28

Medium

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


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

29

Medium

What is the function of the suction pressure regulator?


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 limits the suction pressure and protects the compressor from excessively high suction pressure.
It maintains the evaporation pressure at a constant level.

30

Medium

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

Medium

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

Medium

What properties should good insulation materials have?


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

33

Medium

When is refrigerant vapour superheated?


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

34

Medium

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


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

35

Medium

Where does the liquid line run?


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

36

Medium

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

Medium

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


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

38

Medium

Where should the liquid receiver be installed?


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

39

Medium

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


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

40

Medium

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


An increase in the amount of refrigerant in the system and an increase in condensing pressure.
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.

41

Medium

Which refrigerants belong to the HFC group?


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

42

Medium

Which refrigerants belong to the HFO group?


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

43

Medium

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 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 R407C is 150% higher than that of R410A.

44

Medium

What does the TEWI indicator define?


The impact of a refrigerant on the ozone layer
The global warming potential of a gas relative to CO₂ over a 100-year horizon
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 ability of the ozone layer to recover

45

Medium

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
The temperature glide of R452A is half that of R404A
Both are azeotropic and have no temperature glide
It is a flammable and toxic single-component HFC

46

Medium

What distinguishes R1234yf from R134a?


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

47

Medium

How does CO₂ (R744) compare with R134a?


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

48

Medium

Which of the following is NOT a fluorinated greenhouse gas?


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

49

Medium

What is the greenhouse effect?


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

50

Medium

How do refrigeration systems contribute to the greenhouse effect?


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

51

Medium

What is the greenhouse effect?


The formation of a layer that traps only heat from fuel combustion in aircraft
The filtering of solar radiation by the atmosphere
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

52

Medium

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


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

53

Medium

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


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

54

Medium

What are the ecodesign obligations of manufacturers of refrigerating appliances?


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

55

Medium

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


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

56

Medium

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


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

57

Medium

How do certain gases contribute to the greenhouse effect?


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

58

Medium

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


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

59

Medium

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
It drains excess refrigerant into the receiver
It restricts oil flow
To maintain a constant pressure in the compressor

60

Medium

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


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

61

Medium

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 stores refrigerant; checking its liquid level helps detect charge loss
It controls the evaporating temperature by varying the circulating charge
It regulates the oil returning to the compressor

62

Medium

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


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

63

Medium

What is the role of defrost controls?


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

64

Medium

Where can the lists of fluorinated greenhouse gases be found?


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

65

Medium

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


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

66

Medium

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


By 28 February of the following year, electronically via the Reports Database (BDS) run at the Institute of Industrial Chemistry (ICHP)
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 31 January, in the Central Register of Operators (CRO)

67

Medium

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


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

68

Medium

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

69

Medium

Regulation (EU) 2024/590 relates to:


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

70

Medium

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

71

Medium

Which maintenance measure reduces compressor energy consumption?


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

72

Medium

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


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

73

Medium

What role do controls play in compressor efficiency?


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

74

Medium

How does suction superheat at the compressor affect efficiency?


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

75

Medium

How does correct system layout affect efficiency?


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

76

Medium

How important is suction pipe insulation?


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

77

Medium

Which measure most improves condenser energy efficiency?


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

78

Medium

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

79

Medium

How does correct condensing pressure control affect efficiency?


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

80

Medium

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


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

81

Medium

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


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

82

Medium

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


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

83

Medium

How does too 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 increases operational safety
It has no effect
It reduces refrigerant flow

84

Medium

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


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

85

Medium

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


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
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

86

Medium

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

87

Medium

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


The manufacturer's logo, the unit weight and year of manufacture from the rating plate
Only the trade name of the refrigerant and the unit's serial number
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

88

Medium

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


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

89

Medium

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.

90

Medium

Where are oil traps installed on the suction line?


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

91

Medium

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


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

92

Medium

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


Only high-pressure-side components
Hermetic compressors, liquid receivers and liquid separators
Only suction-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

93

Medium

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 chosen by the technician based on experience
A pressure equal to the maximum pressure measured during operation

94

Medium

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


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

95

Medium

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


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

96

Medium

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?


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

97

Medium

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


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

98

Medium

What electronic equipment should be used for leak checking?


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

99

Medium

What documentation should be checked before starting a leak check?


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

100

Medium

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
Only the number of leaks found and the date of the check
The method used, the time spent on site and the cost of repair

101

Medium

What pressure should be used for the pressure tightness test?


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

102

Medium

What is the temperature glide of a refrigerant?


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

103

Medium

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 ≥ 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
Equipment with 5 t CO₂ eq or more of F-gases, regardless of equipment type

104

Medium

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


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

105

Medium

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


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

106

Medium

Why is it advisable to subcool the liquid refrigerant?


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

107

Medium

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
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
Visually inspect only the bolted and brazed joints near the repair

108

Medium

Recovery of fluorinated greenhouse gases means:


The reuse of fluorinated greenhouse gases following a basic purification process.
The reprocessing of fluorinated greenhouse gases to achieve their specified standard properties.
The collection and storage of fluorinated greenhouse gases from containers, products and equipment during maintenance or servicing or prior to their disposal.
The final decommissioning and withdrawal from service or use of a product or piece of equipment containing fluorinated greenhouse gases.

109

Medium

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


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)
The administrator of the operator's account in the register

110

Medium

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 disposable (non-refillable) cylinder that held the same refrigerant
In a labelled recovery cylinder with a dual valve and a valid inspection

111

Medium

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


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

112

Medium

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


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

113

Medium

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


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

114

Medium

How does push-pull refrigerant recovery work?


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

115

Medium

What are the options for managing waste refrigerant?


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

116

Medium

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


Destruction
Recycling
Storage
Reclamation

117

Medium

The lower the evaporating temperature, …


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

118

Medium

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


Only with weight and capacity marks
With the manufacturer's logo and date of manufacture
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
The marking is optional

119

Medium

The recovery of refrigerants does not require the use of:


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

120

Medium

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 condenses the refrigerant.
The compressor compresses ambient air and increases the pressure of the refrigerant.

121

Medium

What is compressor flooding (liquid slugging)?


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

122

Medium

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


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

123

Medium

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


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.
Because the motor speed would decrease, and consequently the compressor’s capacity.

124

Medium

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


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

125

Medium

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


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

126

Medium

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


Check whether the whole evaporator surface is covered with an even layer of frost
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 liquid distributor upstream of the evaporator feels warm

127

Medium

Why is the compressor crankcase heated?


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

128

Medium

What are compressor packs (racks)?


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

129

Medium

What is the main advantage of multi-compressor packs?


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

130

Medium

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


The capacity, refrigerant type and dimensions of the compressor
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
A range determined only by the evaporating temperature

131

Medium

What are the basic functions of oil in a compressor?


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

132

Medium

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


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

133

Medium

What does hot-gas bypass capacity control involve?


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

134

Medium

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


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

135

Medium

How does a scroll compressor work?


A scroll compressor is also known as a turbo compressor.
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.
It is a type of piston-type device.

136

Medium

What physical process takes place in the evaporator?


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

137

Medium

What is the purpose of compressor capacity control?


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

138

Medium

Why is inverter speed control advantageous for refrigeration compressors?


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

139

Medium

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


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

140

Medium

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


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

141

Medium

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.
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.
The compressor compresses ambient air and increases the pressure of the refrigerant.

142

Medium

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


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

143

Medium

What is the function of the condenser in refrigeration systems?


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

144

Medium

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


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

145

Medium

How is liquid subcooling usually achieved in a refrigeration system?


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

146

Medium

What is the purpose of condenser fan speed control?


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

147

Medium

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


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

148

Medium

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


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

149

Medium

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


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

150

Medium

Who may purchase HFCs for servicing refrigeration equipment?


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

151

Medium

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


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

152

Medium

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?


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

153

Medium

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


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

154

Medium

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


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

155

Medium

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


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

156

Medium

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

157

Medium

What is floating head pressure and what does it achieve?


It increases subcooling by flooding the condenser
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)
It means switching condenser fans off periodically
It keeps a constant high condensing pressure all year

158

Medium

How do SEER/SCOP differ from EER/COP?


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)
EER/COP are always higher than SEER/SCOP

159

Medium

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


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

160

Medium

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


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

161

Medium

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


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