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

2

Közepes

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


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

3

Közepes

Why does heat flow from the condenser to the surroundings?


Because the compressor pushes heat directly into 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 HFC refrigerants attract heat from the surroundings
Because the pressure in the condenser is lower than ambient

4

Közepes

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


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

5

Közepes

What criteria should be considered when selecting a suitable condenser?


Fan noise, connection diameters and colour
Only the size and number of fans
Only own experience and the dimensions
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 increase the heat transfer area and reduce the condensing pressure.
Contaminants restrict heat transfer (reducing the heat transfer coefficient) and cause a reduction in condensing pressure.
Contaminants do not significantly affect the efficiency and effectiveness of the heat exchange surfaces in condensers.
Contaminants restrict heat transfer (reducing the heat transfer coefficient) and cause an increase in condensing temperature and pressure, which in turn leads to a reduction in the condenser’s efficiency.

7

Közepes

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


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

8

Közepes

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


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

9

Közepes

What happens when the evaporation temperature drops?


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

10

Közepes

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


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

11

Közepes

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


Always, in every air cooler
Only when the system runs continuously
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…


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

13

Közepes

How does hot gas defrosting of the evaporator work?


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

14

Közepes

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


It evaporates the water flowing through the evaporator.
It cools the refrigerant.
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.

15

Közepes

What condition must electric heaters for evaporator defrosting meet?


Heat from the heaters must be carried by the running fans
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

16

Közepes

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.
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.

17

Közepes

What defrosting methods are used for air coolers?


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

18

Közepes

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


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

19

Közepes

MOP in thermostatic expansion valves stands for:


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

20

Közepes

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


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

21

Közepes

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


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

22

Közepes

What does a thermostatic expansion valve control?


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

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 superheat value during valve operation.
the degree of refrigerant expansion.

24

Közepes

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


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

25

Közepes

What does a thermostatic or electronic expansion valve control?


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

26

Közepes

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 limits subcooling
The valve maintains a constant condensing pressure
The valve prevents motor overheating by injecting liquid into the compressor

27

Közepes

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


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

28

Közepes

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)
Higher by approx. 20 K
Freely – the MOP value is irrelevant
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 maintains the evaporation pressure at a constant level.
It limits the suction pressure and protects the compressor from excessively high suction pressure.
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 highest possible level.
To maintain the condensing pressure at a constant level.
To maintain the condensing pressure at the lowest possible level.
To maintain the water temperature at the highest level.

31

Közepes

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


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

32

Közepes

What properties should good insulation materials have?


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

33

Közepes

When is refrigerant vapour superheated?


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

34

Közepes

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


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

35

Közepes

Where does the liquid line run?


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

36

Közepes

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


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

37

Közepes

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


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
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 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

Közepes

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

Közepes

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

41

Közepes

Which refrigerants belong to the HFC group?


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

42

Közepes

Which refrigerants belong to the HFO group?


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

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 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

Közepes

What does the TEWI indicator define?


The impact of a refrigerant on the ozone layer
The ability of the ozone layer to recover
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

45

Közepes

What are the characteristics of R452A compared with R404A?


Both are azeotropic and have no temperature glide
It is a flammable and toxic single-component HFC
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

46

Közepes

What distinguishes R1234yf from R134a?


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

47

Közepes

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

Közepes

Which of the following is NOT a fluorinated greenhouse gas?


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

49

Közepes

What is the greenhouse effect?


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
Chlorine compounds destroy stratospheric ozone, increasing UV radiation at the surface

50

Közepes

How do refrigeration systems contribute to the greenhouse effect?


Through oil emitted into the atmosphere from the condenser and filter
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)

51

Közepes

What is the greenhouse effect?


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
The absorption of solar radiation by the Earth's surface

52

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

53

Közepes

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


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

54

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 declaring F-gas quantities under Regulation (EU) No 517/2014
Only implementing an ISO 9001 quality management system
Only using energy labels under Regulation (EU) 2024/573

55

Közepes

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


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

56

Közepes

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


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

57

Közepes

How do certain gases contribute to the greenhouse effect?


They deplete the ozone layer, so more solar radiation reaches the surface
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 trap thermal radiation that the Earth would otherwise emit into space

58

Közepes

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


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

59

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

60

Közepes

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


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

61

Közepes

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


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

62

Közepes

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


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

63

Közepes

What is the role of defrost controls?


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

64

Közepes

Where can the lists of fluorinated greenhouse gases be found?


In the national Act on ozone-depleting substances and certain fluorinated greenhouse gases
In the Vienna Convention for the Protection of the Ozone Layer
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

65

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 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
In the Vienna Convention for the Protection of the Ozone Layer

66

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 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)
By 31 March, electronically to the Ministry of Climate and Environment
By 28 February of the following year, electronically via the Reports Database (BDS) run at the Institute of Industrial Chemistry (ICHP)

67

Közepes

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)
Charging extra refrigerant 'as a reserve' above the nameplate value
Omitting the filter-drier to reduce flow resistance

68

Közepes

How does regular oil-level monitoring affect compressor operation?


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

69

Közepes

Regulation (EU) 2024/590 relates to:


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

70

Közepes

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


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

71

Közepes

Which maintenance measure reduces compressor energy consumption?


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

72

Közepes

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


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

73

Közepes

What role do controls play in compressor efficiency?


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

74

Közepes

How does suction superheat at the compressor affect efficiency?


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

75

Közepes

How does correct system layout affect efficiency?


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

76

Közepes

How important is suction pipe insulation?


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

77

Közepes

Which measure most improves condenser energy efficiency?


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

78

Közepes

Which refrigerants damage the ozone layer?


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

79

Közepes

How does correct condensing pressure control affect efficiency?


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

80

Közepes

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


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

81

Közepes

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


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

82

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 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

Közepes

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


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

84

Közepes

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


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

85

Közepes

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


The compressor runs at a lower load and the suction pressure drops
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
Even under a very small heat load, frost forms on the suction line

86

Közepes

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


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

87

Közepes

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


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
The manufacturer's logo, the unit weight and year of manufacture from the rating plate
That it contains an F-gas, its designation, quantity in kg and t CO₂ eq, and GWP

88

Közepes

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


The make and model 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 owner, installer and service technician of the unit

89

Közepes

Who is responsible for keeping the equipment records?


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

90

Közepes

Where are oil traps installed on the suction line?


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

91

Közepes

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


Sight glass full of liquid and rising oil level in the crankcase
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

92

Közepes

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


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

93

Közepes

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


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

94

Közepes

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


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

95

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

96

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?


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

97

Közepes

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


In any way
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

98

Közepes

What electronic equipment should be used for leak checking?


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

99

Közepes

What documentation should be checked before starting a leak check?


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

100

Közepes

What information must be recorded in the leak check report?


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
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

101

Közepes

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

Közepes

What is the temperature glide of a refrigerant?


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
The temperature rise of the vapour in the compressor

103

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

104

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

105

Közepes

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


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

106

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

107

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

108

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 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 reuse of fluorinated greenhouse gases following a basic purification process.

109

Közepes

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


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

110

Közepes

How must recovered refrigerants be stored?


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

111

Közepes

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

112

Közepes

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


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

113

Közepes

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

Közepes

How does push-pull refrigerant recovery work?


The recovery unit draws vapour from the system and condenses it in the cylinder
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
Nitrogen is injected into the system, pushing the refrigerant into the atmosphere

115

Közepes

What are the options for managing waste refrigerant?


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

116

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
Destruction
Reclamation

117

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 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

118

Közepes

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


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
With the manufacturer's logo and date of manufacture
Only with weight and capacity marks

119

Közepes

The recovery of refrigerants does not require the use of:


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

120

Közepes

What functions does the compressor perform in a refrigeration system?


The compressor compresses ambient air and increases the pressure of the refrigerant.
The compressor draws in refrigerant vapour from the evaporator, compresses it, and then forces it into the condenser, raising the pressure to the required condensing pressure.
The compressor condenses the refrigerant.
The compressor creates a vacuum on the suction side of the system

121

Közepes

What is compressor flooding (liquid slugging)?


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

122

Közepes

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


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

123

Közepes

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

Közepes

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


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

125

Közepes

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


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

126

Közepes

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


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

127

Közepes

Why is the compressor crankcase heated?


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

128

Közepes

What are compressor packs (racks)?


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

129

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

130

Közepes

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


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
A range determined by the evaporating temperature at a given ambient temperature
The capacity, refrigerant type and dimensions of the compressor

131

Közepes

What are the basic functions of oil in a compressor?


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

132

Közepes

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


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

133

Közepes

What does hot-gas bypass capacity control involve?


High-pressure liquid is injected into the suction to increase capacity
The compressor speed is varied
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

134

Közepes

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

135

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.

136

Közepes

What physical process takes place in the evaporator?


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

137

Közepes

What is the purpose of compressor capacity control?


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

138

Közepes

Why is inverter speed control advantageous for refrigeration compressors?


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

139

Közepes

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


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

140

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?


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

141

Közepes

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


This compressor draws in refrigerant vapour from the evaporator, compresses it and then forces it into the condenser whilst the vehicle’s engine is running.
This compressor creates a vacuum on the suction side of the system whilst the vehicle’s engine is switched off.
This compressor condenses the refrigerant whilst the vehicle is in motion.
The compressor compresses ambient air and increases the pressure of the refrigerant.

142

Közepes

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


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

143

Közepes

What is the function of the condenser in refrigeration systems?


Releasing only the heat from the compressor into the surroundings
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
Absorption of heat rejected in the regenerative heat exchanger

144

Közepes

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


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

145

Közepes

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)
By dissolving the refrigerant in oil
With hot high-pressure vapour

146

Közepes

What is the purpose of condenser fan speed control?


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

147

Közepes

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


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

148

Közepes

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


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

149

Közepes

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


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
Yes, always

150

Közepes

Who may purchase HFCs for servicing refrigeration equipment?


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

151

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
When evidence is provided that installation will be carried out by a certified undertaking
Only if the unit contains less than 3 kg of refrigerant
Unconditionally

152

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 2025
By 12 March 2029 (and then at least every 7 years)

153

Közepes

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


Apply for an extension without training
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)
Nothing – Category I automatically becomes A1

154

Közepes

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


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

155

Közepes

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 – independently, for 6 months
Yes – with no time limit, if employed by a certified company
No, never

156

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

157

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)

158

Közepes

How do SEER/SCOP differ from EER/COP?


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

159

Közepes

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


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

160

Közepes

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


Only the date of the check
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
Only the equipment's energy consumption

161

Közepes

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


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