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?


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

2

Közepes

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


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

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

5

Közepes

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

Közepes

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


Contaminants restrict heat transfer (reducing the heat transfer coefficient) and cause an increase in condensing temperature and pressure, which in turn leads to a reduction in the condenser’s efficiency.
Contaminants do not significantly affect the efficiency and effectiveness of the heat exchange surfaces in condensers.
Contaminants increase the heat transfer area and reduce the condensing pressure.
Contaminants restrict heat transfer (reducing the heat transfer coefficient) and cause a reduction in condensing pressure.

7

Közepes

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


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

8

Közepes

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


An increase in condenser subcooling
A rise in evaporating pressure
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

Közepes

What happens when the evaporation temperature drops?


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

10

Közepes

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


Only in coolers fitted with speed-controlled fans
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

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
Only when the room air temperature falls below 0 °C
When the evaporator surface temperature is below 0 °C and below the dew point of the air

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.
This involves reversing the direction of rotation of the compressor.
We swap the outlet and inlet sides of the evaporator.
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 transfers heat from the medium being cooled to the boiling refrigerant.
It evaporates the water flowing through the evaporator.
It cools the refrigerant.
It ensures that the refrigerant is superheated over the largest possible heat exchange surface area.

15

Közepes

What condition must electric heaters for evaporator defrosting meet?


They must be located beneath the evaporator
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 in direct contact with the refrigerant

16

Közepes

Refrigerant distributor:


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

17

Közepes

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

Közepes

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


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

19

Közepes

MOP in thermostatic expansion valves stands for:


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

20

Közepes

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


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

21

Közepes

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


A 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

Közepes

What does a thermostatic expansion valve control?


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

23

Közepes

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


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

24

Közepes

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


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

25

Közepes

What does a thermostatic or electronic expansion valve control?


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

26

Közepes

What does the MOP function of thermostatic expansion valves mean?


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

27

Közepes

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


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

28

Közepes

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


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

29

Közepes

What is the function of the suction pressure regulator?


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.
It prevents a drop in suction pressure and, if necessary, shuts down the refrigeration system.

30

Közepes

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


To maintain the condensing pressure at a constant level.
To maintain the condensing pressure at the lowest possible level.
To maintain the condensing pressure at the highest 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 a MOP function.
... with external pressure equalisation.
... with an adsorption-type sensor filling.
... with internal pressure equalisation.

32

Közepes

What properties should good insulation materials have?


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

33

Közepes

When is refrigerant vapour superheated?


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

34

Közepes

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


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

35

Közepes

Where does the liquid line run?


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

36

Közepes

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


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
To collect liquid refrigerant and excess oil

37

Közepes

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


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

38

Közepes

Where should the liquid receiver be installed?


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

39

Közepes

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


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

40

Közepes

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


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

41

Közepes

Which refrigerants belong to the HFC group?


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

42

Közepes

Which refrigerants belong to the HFO group?


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

43

Közepes

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


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

44

Közepes

What does the TEWI indicator define?


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


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
Both are azeotropic and have no temperature glide
The temperature glide of R452A is half that of R404A

46

Közepes

What distinguishes R1234yf from R134a?


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

47

Közepes

How does CO₂ (R744) compare with R134a?


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

48

Közepes

Which of the following is NOT a fluorinated greenhouse gas?


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

49

Közepes

What is the greenhouse effect?


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

50

Közepes

What is R1270?


n-Butane
Propane
Propene (propylene)
Isobutane

51

Közepes

How do refrigeration systems contribute to the greenhouse effect?


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

52

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

53

Közepes

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


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

54

Közepes

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


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

55

Közepes

What are the ecodesign obligations of manufacturers of refrigerating appliances?


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
Only implementing an ISO 9001 quality management system

56

Közepes

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


To 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

57

Közepes

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


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

58

Közepes

How do certain gases contribute to the greenhouse effect?


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

59

Közepes

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


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

60

Közepes

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


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

61

Közepes

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


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

62

Közepes

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


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
It keeps the whole system at constant pressure regardless of load

63

Közepes

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


It monitors refrigerant moisture content
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)

64

Közepes

What is the role of defrost controls?


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

65

Közepes

Where can the lists of fluorinated greenhouse gases be found?


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

66

Közepes

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


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
In a regulation of the Minister of the Environment on the list of controlled substances

67

Közepes

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


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

68

Közepes

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


By 31 January, in the Central Register of Operators (CRO)
By 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)

69

Közepes

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


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

70

Közepes

How does regular oil-level monitoring affect compressor operation?


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

71

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

72

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

73

Közepes

Which maintenance measure reduces compressor energy consumption?


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

74

Közepes

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


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

75

Közepes

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

76

Közepes

How does suction superheat at the compressor affect efficiency?


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

77

Közepes

How does correct system layout affect efficiency?


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

78

Közepes

How important is suction pipe insulation?


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

79

Közepes

Which measure most improves condenser energy efficiency?


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

80

Közepes

Which refrigerants damage the ozone layer?


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

81

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

82

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 doesn't matter
It increases pressure

83

Közepes

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


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

84

Közepes

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


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
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)

85

Közepes

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


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

86

Közepes

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


Design requirements and conformity assessment for pressure equipment
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
Only requirements for periodic leak checks of refrigeration equipment

87

Közepes

What is the main design difference in hydrocarbon refrigeration systems?


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

88

Közepes

How do compressors used in hydrocarbon systems differ?


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

89

Közepes

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

90

Közepes

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


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

91

Közepes

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

92

Közepes

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


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

93

Közepes

Who is responsible for keeping the equipment records?


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

94

Közepes

Where are oil traps installed on the suction line?


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

95

Közepes

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


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

96

Közepes

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


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

97

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
The pressure specified in EN 378-2 or by the manufacturer, not exceeding the maximum allowable pressure of the system (PS)
A pressure equal to the maximum pressure measured during operation

98

Közepes

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


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

99

Közepes

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


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
When gas bubbles appear after immersion in water

100

Közepes

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


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

101

Közepes

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


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

102

Közepes

What electronic equipment should be used for leak checking?


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

103

Közepes

What documentation should be checked before starting a leak check?


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

104

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

105

Közepes

What pressure should be used for the pressure tightness test?


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

106

Közepes

What is the temperature glide of a refrigerant?


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

107

Közepes

In which equipment is a leakage detection system required?


Equipment with 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
Equipment with 50 t CO₂ eq or more of F-gases, regardless of equipment type

108

Közepes

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


That it has an infrared sensor, as only this type is permitted
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

109

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

110

Közepes

Why is it advisable to subcool the liquid refrigerant?


To allow a smaller expansion valve to be used
To lower the evaporating temperature in the evaporator
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

111

Közepes

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


Issue the invoice and leave the leak check to the next periodic service
Charge an alternative refrigerant, start up and measure the parameters
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)

112

Közepes

Recovery of fluorinated greenhouse gases means:


The final decommissioning and withdrawal from service or use of a product or piece of equipment containing fluorinated greenhouse gases.
The 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.
The reprocessing of fluorinated greenhouse gases to achieve their specified standard properties.

113

Közepes

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


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

114

Közepes

How must recovered refrigerants be stored?


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

115

Közepes

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


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

116

Közepes

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


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

117

Közepes

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


Separate the mixture into its components yourself
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

118

Közepes

How does push-pull refrigerant recovery work?


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 system and condenses it in the cylinder
The recovery unit draws vapour from the recovery cylinder and pushes it into the system; the pressure difference forces liquid refrigerant out of the system into the cylinder

119

Közepes

What are the options for managing waste refrigerant?


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

120

Közepes

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


Destruction
Reclamation
Recycling
Storage

121

Közepes

The lower the evaporating temperature, …


…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 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 lower the refrigerant mass flow rate

122

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

123

Közepes

The recovery of refrigerants does not require the use of:


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

124

Közepes

What functions does the compressor perform in a refrigeration 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.
The compressor creates a vacuum on the suction side of the system

125

Közepes

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
Liquid refrigerant or oil entering the compression chamber
Excess oil in the condenser

126

Közepes

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


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
By a maximum of 10%

127

Közepes

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


Because this type of compressor has difficulty starting up if the phase sequence is changed.
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 the motor speed would decrease, and consequently the compressor’s capacity.

128

Közepes

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


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

129

Közepes

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


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

130

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 by touch whether the condenser outlet is noticeably colder than ambient
Check whether the whole evaporator surface is covered with an even layer of frost
Check whether the liquid distributor upstream of the evaporator feels warm

131

Közepes

Why is the compressor crankcase heated?


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

132

Közepes

What are compressor packs (racks)?


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

133

Közepes

What is the main advantage of multi-compressor packs?


No need for compressor controls and safety devices
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

134

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

135

Közepes

What are the basic functions of oil in a compressor?


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

136

Közepes

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


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

137

Közepes

What does hot-gas bypass capacity control involve?


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
Bypass is not used for capacity control
High-pressure liquid is injected into the suction to increase capacity

138

Közepes

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


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

139

Közepes

How does a scroll compressor work?


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

140

Közepes

What physical process takes place in the evaporator?


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

141

Közepes

What is the purpose of compressor capacity control?


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

142

Közepes

Why is inverter speed control advantageous for refrigeration compressors?


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

143

Közepes

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


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

144

Közepes

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


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

145

Közepes

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


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.
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.

146

Közepes

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


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

147

Közepes

What is the function of the condenser in refrigeration systems?


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

148

Közepes

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


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

149

Közepes

How is liquid subcooling usually achieved in a refrigeration system?


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

150

Közepes

What is the purpose of condenser fan speed control?


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

151

Közepes

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


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

152

Közepes

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


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

153

Közepes

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


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

154

Közepes

Who may purchase HFCs for servicing refrigeration equipment?


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

155

Közepes

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
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

156

Közepes

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


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

157

Közepes

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


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

158

Közepes

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


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

159

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

160

Közepes

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


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

161

Közepes

What distinguishes class 2L refrigerants from class 2?


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

162

Közepes

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


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

163

Közepes

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


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

164

Közepes

How is explosion hazard zone 2 defined?


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

165

Közepes

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


UN 1978
UN 1005
UN 3252
UN 3337

166

Közepes

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


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

167

Közepes

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


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

168

Közepes

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


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

169

Közepes

Which property of ammonia helps people detect a leak early?


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

170

Közepes

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


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

171

Közepes

What is floating head pressure and what does it achieve?


It keeps a constant high condensing pressure all year
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 increases subcooling by flooding the condenser

172

Közepes

How do SEER/SCOP differ from EER/COP?


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

173

Közepes

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


Adding a second liquid receiver
Larger liquid-line diameters
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

174

Közepes

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


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

175

Közepes

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


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

176

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