F-Gas English Low GWP
All questions
HFC | Flammable | CO₂ | NH₃
Easy questions |
Medium questions |
Difficult questions
1
Easy
What is the base unit of mass in the International System of Units (SI)?
| kg |
| N |
| t |
| lb (pound) |
2
Medium
What process takes place in the condenser of a refrigeration system?
| 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 secondary fluid (glycol, water) condenses while the refrigerant evaporates |
| The refrigerant absorbs heat from the surroundings and evaporates |
3
Medium
What mainly determines the condensing temperature of an air-cooled condenser?
| The ambient (inlet) air temperature |
| The superheat |
| The evaporating temperature |
| The compressor discharge temperature |
4
Medium
Why does heat flow from the condenser to the surroundings?
| Because the condensing temperature is higher than the ambient temperature, and heat flows spontaneously from a warmer to a colder body (second law of thermodynamics) |
| Because the compressor pushes heat directly into the surroundings |
| Because HFC refrigerants attract heat from the surroundings |
| Because the pressure in the condenser is lower than ambient |
5
Medium
What should you mainly pay attention to when operating a condenser?
| The colour of the condenser casing |
| That the outlet air temperature is higher than the condensing temperature |
| Its general condition and the cleanliness of the heat-exchange surfaces |
| That the inlet air temperature is lower than the outlet air temperature |
6
Medium
What criteria should be considered when selecting a suitable condenser?
| The required capacity of the condenser and the technical specifications declared by the manufacturer |
| Fan noise, connection diameters and colour |
| Only own experience and the dimensions |
| Only the size and number of fans |
7
Medium
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 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. |
8
Medium
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 decreases |
| It increases |
9
Medium
What is the main consequence of heavy frost on an air-cooling evaporator?
| A rise in evaporating pressure |
| An increase in condenser subcooling |
| Reduced heat transfer and airflow, resulting in a drop in cooling capacity and evaporating temperature |
| A rise in the cooled-air temperature with no effect on capacity |
10
Medium
What happens when the evaporation temperature drops?
| The compressor’s cooling capacity increases. |
| The condenser fan speed increases. |
| The compressor’s cooling capacity decreases. |
| The discharge temperature decreases. |
11
Medium
When is natural (off-cycle, air) defrosting possible?
| Never – electric heaters must be used in every air cooler |
| Only in freezer rooms below −18 °C |
| When the air passing through the cooler is above 0 °C |
| Only in coolers fitted with speed-controlled fans |
12
Medium
When does frost form on the surface of an air-cooling evaporator?
| Only when the room air temperature falls below 0 °C |
| 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 |
13
Medium
In extensive pipework systems, flash gas (secondary evaporation) in the liquid line can be prevented by…
| …using smaller-diameter pipes |
| …additional subcooling of the liquid |
| …increasing the length of the liquid line |
| …insulating the discharge line between the compressor and the condenser |
14
Medium
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. |
| Heated vapour (hot gas) from the compressor is directed into the evaporator piping. |
| We swap the outlet and inlet sides of the evaporator. |
15
Medium
What is the function of the evaporator in a refrigeration system?
| It evaporates the water flowing through the evaporator. |
| It transfers heat from the medium being cooled to the boiling refrigerant. |
| It ensures that the refrigerant is superheated over the largest possible heat exchange surface area. |
| It cools the refrigerant. |
16
Medium
What condition must electric heaters for evaporator defrosting meet?
| They must have good thermal contact with the heat-exchange surface (e.g. inserted in the fin block) |
| They must be located beneath the evaporator |
| Heat from the heaters must be carried by the running fans |
| They must be in direct contact with the refrigerant |
17
Medium
Refrigerant distributor:
| acts as a buffer for the refrigerant in the event that the pressure upstream of the expansion valve is exceeded. |
| ensures an even distribution of the refrigerant to the individual sections of the evaporator. |
| ensures even distribution of the refrigerant to the individual sections of the condenser. |
| ensures the even distribution of the refrigerant discharged by compressors connected in parallel. |
18
Medium
What defrosting methods are used for air coolers?
| Natural only – other methods are ineffective and uneconomic |
| Electric, hot gas, water spray and natural (at positive temperatures) |
| Only by switching off the fans with the compressor running |
| Electric only – other methods are not permitted in refrigeration |
19
Medium
The boiling point of a liquid rises when the pressure above the liquid…
| …remains constant |
| …falls |
| …rises |
| …varies depending on the ambient temperature |
20
Medium
MOP in thermostatic expansion valves stands for:
| maximum operating pressure. |
| maximum pressure switch protection. |
| self-cleaning of the valve in the event of moisture in the refrigerant freezing. |
| minimum flow opening. |
21
Medium
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 |
22
Medium
What type of compressor motor can be used with a capillary tube?
| A high-starting-torque motor must be used |
| A low-speed motor |
| A low-starting-torque motor (pressures equalise during standstill) |
| An electronically commutated motor |
23
Medium
What does a thermostatic expansion valve control?
| The discharge temperature |
| The condensing pressure |
| The mass flow of refrigerant fed into the evaporator |
| The temperature in the cold room |
24
Easy
The refrigerant absorbs heat when…
| …it condenses |
| …it evaporates |
| …it freezes |
| …it is subcooled |
25
Medium
What does the manufacturer state as the factory setting of a thermostatic expansion valve?
| the superheat value during valve operation. |
| the degree of refrigerant expansion. |
| the static superheat of the valve. |
| the degree to which the valve is filled with refrigerant liquid. |
26
Medium
Where is a new or repaired system with an expansion valve and liquid receiver charged?
| Anywhere – the charging point does not matter |
| Through the capillary tube outlet during normal system operation |
| In the liquid phase into the compressor suction, with the compressor running |
| In the liquid phase on the high-pressure side, with the compressor stopped |
27
Medium
What does a thermostatic or electronic expansion valve control?
| Subcooling, by adjusting condensing pressure |
| The compressor speed |
| The evaporating pressure – closing below the set point |
| The amount of refrigerant fed to the evaporator according to superheat |
28
Medium
What does the MOP function of thermostatic expansion valves mean?
| The valve prevents motor overheating by injecting liquid into the compressor |
| The valve maintains a constant condensing pressure |
| The valve limits the maximum evaporating (suction) pressure, protecting the compressor motor from overload, e.g. after defrost |
| The valve limits subcooling |
29
Medium
The lower the liquid temperature upstream of the expansion valve, (at the same mass flow)…
| …the lower qo and the lower energy efficiency |
| …the lower qo, with Qo unchanged |
| …the higher the specific refrigerating effect qo [kJ/kg] and the higher the cooling capacity Qo |
| …the lower qo and the lower Qo |
30
Medium
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 |
| Higher by approx. 20 K |
| Freely – the MOP value is irrelevant |
| A few kelvin higher (approximately 7 K) |
31
Medium
What is the function of the suction pressure regulator?
| It prevents a drop in suction pressure and, if necessary, shuts down the refrigeration system. |
| It maintains the evaporation pressure at a constant level. |
| To maintain the suction pressure at the highest possible level. |
| It limits the suction pressure and protects the compressor from excessively high suction pressure. |
32
Medium
What is the function of the valve regulating water flow through the condenser?
| To maintain the water temperature at the highest level. |
| 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. |
33
Medium
The use of a refrigerant distributor requires a thermostatic expansion valve ...
| ... with external pressure equalisation. |
| ... with internal pressure equalisation. |
| ... with an adsorption-type sensor filling. |
| ... with a MOP function. |
34
Medium
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) |
35
Medium
When is refrigerant vapour superheated?
| When the compressor motor temperature rises excessively |
| When the evaporating temperature is lower than the ambient temperature |
| When the pressure on the discharge side is higher than on the suction side |
| When its temperature is higher than the saturation temperature corresponding to its pressure |
36
Medium
How can you check whether the liquid refrigerant is reaching the expansion valve without vapour bubbles?
| 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. |
| We are unable to check this. |
37
Medium
Where does the liquid line run?
| From the condenser (liquid receiver) to the expansion valve |
| Between the evaporator and the suction-line heat exchanger |
| Between the evaporator and the compressor |
| Between the compressor and the condenser |
38
Medium
What is the function of the liquid receiver in a refrigeration system?
| To act as a reserve when the required charge is unknown |
| To collect liquid refrigerant and excess oil |
| To store refrigerant and compensate for changes in the circulating charge as the heat load varies |
| To further subcool the condensed refrigerant |
39
Medium
What is the purpose of the liquid receiver during service work?
| It allows pump-down and temporary storage of the refrigerant |
| It is a reserve when the installer does not know the required charge |
| It further subcools the refrigerant before the expansion valve |
| It collects excess oil circulating in the system |
40
Medium
Where should the liquid receiver be installed?
| It should be fitted just before the compressor. |
| It should be fitted between the compressor and the condenser. |
| It should be fitted after the evaporator. |
| It should be installed downstream of the condenser, upstream of the expansion valve. |
41
Medium
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 closes when the suction pressure upstream of the compressor drops. |
| It regulates the evaporation pressure. |
42
Medium
The use of microchannel heat exchangers, compared with conventional heat exchangers made of copper tubes and fins, results in:
| A reduction in the system’s energy efficiency. |
| A reduction in refrigerant charge and, typically, higher energy efficiency. |
| There is no effect whatsoever on either the amount of refrigerant or energy efficiency. |
| An increase in the amount of refrigerant in the system and an increase in condensing pressure. |
43
Medium
Which refrigerants belong to the HFC group?
| R134a, R32, R22, R507A, R290. |
| R22, R401A. |
| R134a, R404A, R507A, R410A. |
| R11, R12, R502. |
44
Medium
Which refrigerants belong to the HFO group?
| R134a, R404A. |
| R22, R12. |
| R1234yf, R1234ze(E). |
| R134a, R290. |
45
Medium
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 refrigerant is much higher than that of R410A. |
| The saturation pressure of R407C is 150% higher than that of R410A. |
| The saturation pressure of both refrigerants is roughly the same. |
46
Medium
What does the TEWI indicator define?
| 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 |
| The global warming potential of a gas relative to CO₂ over a 100-year horizon |
| The ability of the ozone layer to recover |
47
Medium
What are the characteristics of R452A compared with R404A?
| The temperature glide of R452A is half that of R404A |
| Both are azeotropic and have no temperature glide |
| It is a flammable and toxic single-component HFC |
| It is a non-flammable (A1) HFC/HFO blend with properties similar to R404A and a GWP about 45% lower |
48
Medium
What distinguishes R1234yf from R134a?
| It is mildly flammable (class A2L), whereas R134a is non-flammable (A1) |
| A higher normal boiling point |
| A higher critical temperature |
| Higher toxicity |
49
Medium
How does CO₂ (R744) compare with R134a?
| Its temperature glide is 7 K greater than that of R134a |
| It has identical properties and is a drop-in replacement for R134a |
| Unlike R134a, it is an azeotropic mixture |
| It has a lower critical temperature, much higher operating pressures and a much higher volumetric cooling capacity (smaller compressors and pipes) |
50
Medium
Which of the following is NOT a fluorinated greenhouse gas?
| Perfluorocarbons (PFCs). |
| Carbon dioxide (CO₂). |
| Sulphur hexafluoride (SF6). |
| Hydrofluorocarbons (HFCs). |
51
Medium
What is the greenhouse effect?
| Clouds reflect ultraviolet radiation, which makes the air near the surface warmer |
| Chlorine compounds destroy stratospheric ozone, increasing UV radiation at the surface |
| 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 |
52
Easy
What does the GWP indicator mean?
| The annual rise in mean air temperature caused by the emission of 1 kg of the gas |
| Ozone depletion potential |
| Global Warming Potential: the climate warming impact of 1 kg of a gas compared with 1 kg of CO₂ (GWP = 1) over a defined time horizon, usually 100 years |
| The ability of a substance to restore the ozone layer |
53
Medium
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 |
| Indirectly (through energy consumption) and directly (through emissions of refrigerant into the atmosphere) |
| Only through the heat rejected by the condenser |
54
Medium
What is the greenhouse effect?
| The filtering of solar radiation by the atmosphere |
| The absorption of solar radiation by the Earth's surface |
| The formation of a layer that traps only heat from fuel combustion in aircraft |
| The trapping of heat in the Earth's atmosphere, which hinders the radiation of heat into space |
55
Medium
Which EU regulation is currently the primary piece of legislation governing the use of fluorinated greenhouse gases (F-gases) in the European Union?
| Regulation (EU) 2024/573 |
| Regulation (EU) No 517/2014 |
| Regulation (EU) 2015/1188 |
| Directive 2009/125/EC |
56
Medium
What is the main objective of Regulation (EU) 2024/573?
| To facilitate the import of electrical appliances |
| To reduce taxes on refrigeration equipment |
| Standardising metal recycling standards |
| Prevention of F-gas emissions and the achievement of the EU’s climate targets |
57
Medium
What are the ecodesign obligations of manufacturers of refrigerating appliances?
| Meeting implementing regulations (e.g. 2019/2019, 2015/1095): efficiency, spare parts, reparability |
| Only using energy labels under Regulation (EU) 2024/573 |
| Only implementing an ISO 9001 quality management system |
| Only declaring F-gas quantities under Regulation (EU) No 517/2014 |
58
Medium
What is the main objective of EU ecodesign legislation (Directive 2009/125/EC, now Regulation (EU) 2024/1781 – ESPR)?
| To facilitate imports from outside the EU |
| To increase sales of electrical appliances in the EU |
| To standardise the appearance of products in the EU |
| To reduce the negative environmental impact of products by improving energy efficiency, durability and recyclability |
59
Medium
What is the function of a ball valve in a refrigeration system?
| It prevents excessive pressure build-up in the system |
| It regulates the temperature of the refrigerant |
| Enables the refrigerant flow to be completely shut off |
| It measures the moisture content of the refrigerant |
60
Easy
What is the main function of a safety valve?
| It controls the oil level in the compressor |
| Prevents the evaporator from freezing |
| It monitors the moisture content of the refrigerant |
| Discharges refrigerant when the set pressure is exceeded |
61
Medium
How do certain gases contribute to the greenhouse effect?
| 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 |
| They limit UV radiation reaching the Earth's surface, changing the heat balance |
62
Medium
What is the purpose of a sight glass (with moisture indicator)?
| Regulating compressor pressure |
| Visual assessment of the refrigerant condition in the liquid line (bubbles) and of system moisture |
| Measuring condenser temperature |
| Emergency shut-off of flow |
63
Medium
What is the function of the temperature regulator in a refrigeration system?
| It restricts oil flow |
| Controls the operation of the compressor and valves to maintain the set temperature |
| To maintain a constant pressure in the compressor |
| It drains excess refrigerant into the receiver |
64
Difficult
What is the role of a suction liquid separator (also in systems with flammable or toxic refrigerants)?
| It prevents liquid refrigerant from entering the compressor |
| It heats the refrigerant before the evaporator |
| It separates liquid from oil |
| It is used only to measure moisture |
65
Difficult
What is the function of an oil separator in systems using flammable or toxic refrigerants?
| They are used solely to measure the moisture content of the refrigerant |
| It prevents liquid from entering the compressor |
| Heats the refrigerant before it enters the evaporator |
| Separates oil from the refrigerant and facilitates the return of oil to the compressor |
66
Medium
What is the purpose of oil level regulators in a refrigeration system?
| They control the evaporator temperature |
| They drain off excess refrigerant |
| Maintains the correct oil level in the compressor |
| They control the pressure in the condenser |
67
Medium
What is the function of the liquid receiver in relation to system tightness?
| It regulates the oil returning to the compressor |
| It stores refrigerant; checking its liquid level helps detect charge loss |
| It keeps the whole system at constant pressure regardless of load |
| It controls the evaporating temperature by varying the circulating charge |
68
Medium
What is the role of a gauge manifold with thermometers (temperature probes)?
| It relieves pressure if it is exceeded |
| It measures pressures and temperatures to determine superheat and subcooling and thus assess the system charge (indirect leak check) |
| It controls oil level |
| It monitors refrigerant moisture content |
69
Medium
What is the role of defrost controls?
| They drain excess oil from the evaporator to the receiver |
| They protect the evaporator from icing and damage that could lead to leaks |
| They monitor the moisture content of the refrigerant |
| They control compressor discharge pressure during defrost |
70
Easy
What is the unit of pressure in the International System of Units (SI)?
| psi (pound per square inch) |
| bar (gauge) |
| atm (standard atmosphere) |
| Pa (pascal) |
71
Medium
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 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 |
72
Medium
Where can the lists of ozone-depleting substances 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 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 |
73
Difficult
Why are PFAS formed by the decomposition of certain F-gases (e.g. TFA from HFOs) problematic?
| They are readily biodegradable |
| They cause rapid cooling of the atmosphere |
| They are very persistent, accumulate in the environment (e.g. water) and may be toxic |
| They are climate- and environment-neutral |
74
Medium
Where and by when must entities obliged under the Polish Act of 15 May 2015 submit annual reports on ODS and F-gases?
| By 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) |
| By the end of the calendar year, on a form at a regional office of the Office of Technical Inspection (UDT) |
75
Medium
Which installation measure has a major impact on compressor energy efficiency?
| Proper evacuation and dehydration of the system (removing air and moisture) |
| Charging extra refrigerant 'as a reserve' above the nameplate value |
| Installing a suction line smaller than recommended |
| Omitting the filter-drier to reduce flow resistance |
76
Medium
How does regular oil-level monitoring affect compressor operation?
| It ensures proper lubrication and limits wear and energy losses |
| It increases cooling capacity above nominal |
| It allows any type of oil to be topped up |
| It allows the crankcase heater to be omitted |
77
Easy
How do system leaks affect compressor energy efficiency?
| Refrigerant loss reduces capacity and increases energy use (longer run times, higher superheat) |
| They affect only safety, not energy use |
| They improve efficiency because condensing pressure drops |
| No effect as long as the system still cools |
78
Medium
Regulation (EU) 2024/590 relates to:
| Alternative refrigerants replacing fluorinated greenhouse gases |
| Health and safety during refrigerant recovery |
| Conditions for F-gas certification of companies recovering and reclaiming refrigerants |
| Ozone-depleting substances |
79
Medium
What is the significance of proper suction and discharge pressure control?
| Pressures do not affect energy use |
| The lowest possible suction pressure is best |
| 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 |
80
Medium
Which maintenance measure reduces compressor energy consumption?
| Raising the high-pressure switch setting |
| Replacing the filter-drier when the pressure drop or moisture indicator shows it is necessary |
| Permanently disabling the crankcase heater |
| Topping up refrigerant at every service visit |
81
Medium
How does air (non-condensable gas) in the system affect operation?
| It lowers the condensing pressure |
| It only affects the sight-glass indication |
| It raises the condensing pressure and reduces efficiency |
| It improves condenser heat transfer |
82
Medium
What role do controls play in compressor efficiency?
| They enable optimised operation and lower energy use (e.g. floating head pressure, capacity matching) |
| They matter only in NH₃ systems |
| They provide safety only, with no energy effect |
| They increase the circulating refrigerant charge |
83
Medium
How does suction superheat at the compressor affect efficiency?
| Superheat has no effect |
| Zero suction superheat is optimal |
| Excessive superheat reduces efficiency and raises the discharge temperature |
| The higher the superheat, the higher the efficiency |
84
Medium
How does correct system layout affect efficiency?
| It affects only appearance |
| Longer pipes improve subcooling and always increase efficiency |
| It doesn't matter |
| It shortens pipe runs and limits pressure drops and energy losses |
85
Medium
How important is suction pipe insulation?
| It increases energy consumption |
| It has no effect |
| It limits heat gain and excessive superheat, improving efficiency |
| It is needed only for appearance |
86
Medium
Which measure most improves condenser energy efficiency?
| Regular cleaning of heat-exchange surfaces |
| Reducing fan speed to the minimum |
| Raising the condensing pressure set point |
| Increasing the refrigerant charge |
87
Easy
How does a dirty condenser affect the operation of the refrigeration system?
| Causes an increase in pressure and energy consumption by the compressor |
| It lowers the condensing pressure |
| It has no effect |
| It improves efficiency |
88
Easy
Why is adequate airflow through an air-cooled condenser important?
| It affects only noise |
| The lower the airflow, the lower the condensing pressure |
| It doesn't matter |
| It ensures effective heat rejection and low condensing pressure |
89
Medium
Which refrigerants damage the ozone layer?
| All refrigerants containing fluorine and hydrogen in their molecules |
| All natural refrigerants |
| All refrigerants containing chlorine or bromine in their molecules |
| All refrigerants containing carbon in their molecules |
90
Easy
How does the presence of limescale in a water-cooled condenser affect performance?
| It has no effect |
| It improves heat transfer |
| Impairs heat exchange and increases energy consumption |
| It lowers the condensation temperature |
91
Medium
How does correct condensing pressure control affect efficiency?
| It always increases energy use |
| It has no effect |
| It is best to keep a constant high condensing pressure all year |
| It keeps the lowest pressure that still ensures proper expansion-valve feed, reducing energy use |
92
Easy
How do condenser leaks affect energy efficiency?
| They improve efficiency |
| They lower the temperature |
| Causes refrigerant loss and a drop in efficiency |
| Have no effect |
93
Easy
How important is the correct positioning of an air-cooled condenser?
| It should be close to heat sources |
| It doesn’t matter |
| It should be housed in a small room |
| It should be installed in a well-ventilated area with unobstructed airflow |
94
Easy
How does hot air recirculation affect the condenser?
| It reduces the pressure |
| It improves efficiency |
| Impairs cooling and increases energy consumption |
| It has no effect |
95
Medium
How does insulation of heating and DHW pipework affect the efficiency of a heat pump system?
| It reduces energy losses and improves overall system efficiency |
| It impairs cooling |
| It doesn't matter |
| It increases pressure |
96
Medium
Which measure most improves the energy efficiency of an air-cooling evaporator?
| Raising the condensing temperature by a few kelvin |
| Restricting the airflow through the evaporator |
| Increasing the refrigerant charge above nominal |
| Defrosting at the right time and keeping the fins clean |
97
Easy
How does evaporator icing affect the system’s operation?
| It lowers the condensation temperature |
| It improves cooling performance |
| Impairs heat exchange and increases energy consumption |
| It has no effect |
98
Easy
How does dirt on the evaporator surface affect its performance?
| It reduces the pressure |
| It has no effect |
| It improves efficiency |
| Impairs heat exchange and increases energy consumption |
99
Easy
What maintenance task is crucial for the evaporator?
| Regular cleaning and defrosting |
| Lack of maintenance |
| Reduced airflow |
| Increasing the refrigerant charge |
100
Medium
What does a Certificate A2 for natural persons (Implementing Regulation (EU) 2024/2215) authorise?
| Only leak checks that do not entail breaking into the refrigerant circuit |
| Only recovery of F-gases from equipment containing less than 3 kg (or 6 kg in hermetically sealed systems) |
| All activities (leak checks, installation, repair, maintenance, servicing, decommissioning, recovery) involving F-gases and hydrocarbons in equipment containing less than 3 kg, or less than 6 kg in labelled hermetically sealed systems |
| All activities involving equipment using CO₂ (R744) |
101
Easy
How does superheat at the evaporator outlet affect efficiency?
| It only causes a temperature drop |
| It always improves performance |
| Excessive superheat reduces energy efficiency |
| It has no effect |
102
Easy
How do leaks in the evaporator affect efficiency?
| Have no effect |
| Improves performance |
| These cause refrigerant loss and a drop in efficiency |
| Increase capacity |
103
Easy
How important is correct expansion valve adjustment?
| It increases energy consumption |
| It doesn’t matter |
| Causes leaks |
| Ensures optimal evaporator charge and improves efficiency |
104
Easy
How does inadequate insulation of suction (or secondary-coolant) pipes affect evaporator performance?
| It has no effect |
| It improves efficiency |
| It lowers the condensing temperature |
| It causes cooling losses and increased energy use |
105
Easy
How does correct TEV adjustment affect system energy efficiency?
| It has no effect |
| It causes leaks |
| It increases energy use |
| It ensures optimal superheat and improves efficiency |
106
Easy
What happens if the superheat set by the TEV is too high?
| It has no effect |
| Cooling efficiency will improve |
| Efficiency will drop because the evaporator is not being fully utilised |
| The refrigerant charge will increase |
107
Medium
How does too low superheat setting on the TEV affect performance?
| It may lead to improved efficiency, but it increases the risk of the compressor becoming flooded with liquid |
| It increases operational safety |
| It has no effect |
| It reduces refrigerant flow |
108
Easy
How do contaminants in the system affect the operation of the TEV?
| They lower the temperature |
| They can cause it to become blocked and reduce efficiency |
| Have no effect |
| They improve its performance |
109
Easy
What role does the filter-drier play in terms of system efficiency?
| Removes moisture and contaminants, improving the system’s efficiency |
| It doesn’t matter |
| It lowers the temperature |
| It increases the amount of refrigerant |
110
Easy
How does proper insulation of components (e.g. pipes near the TEV) affect the system?
| It causes leaks |
| Prevents unwanted heat gains and improves efficiency |
| It doesn’t matter |
| It increases energy consumption |
111
Medium
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 |
112
Easy
How important is it to check the operation of the condensing pressure control valve in the system?
| It causes a significant rise in temperature |
| Ensures operation within the optimum pressure range and reduces energy losses |
| It has no effect |
| It increases energy consumption |
113
Easy
How does the correct selection of a TEV affect energy efficiency?
| It doesn’t matter |
| It lowers the temperature |
| Ensures the system is matched to its capacity and operates optimally |
| It increases the amount of refrigerant |
114
Medium
How can you tell that the system has been overcharged with refrigerant?
| Even under a very small heat load, frost forms on the suction line |
| The compressor runs at a lower load and the suction pressure drops |
| It cannot be checked, because the sight glass is not intended for this |
| Under normal operating conditions the condensing pressure and subcooling rise markedly because excess liquid floods the condenser and reduces its active surface |
115
Medium
Before charging the unit with refrigerant, it is essential to…
| …carry out a trial start-up |
| …check the compressor suction and discharge connections |
| …carry out a tightness test (and evacuate the system) |
| …fill in the unit's data sheet |
116
Medium
What information must appear on the label of equipment containing F-gases?
| That it contains an F-gas, its designation, quantity in kg and t CO₂ eq, and GWP |
| Only the trade name of the refrigerant and the unit's serial number |
| The manufacturer's logo, the unit weight and year of manufacture from the rating plate |
| The weight and capacity of the pipework and the colour code of the casing paint |
117
Easy
What is the base unit of temperature according to the International System of Units (Système International d’Unités)?
| K |
| °R |
| °C |
| °F |
118
Medium
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 |
| The owner, installer and service technician of the unit |
| Only the date of installation and the installer's name |
| Operator details, equipment details, type and quantity of refrigerant, and information on servicing and repairs |
119
Difficult
Which statement about installing Schrader valves is correct?
| Schrader valves must not be used in R744 systems |
| When brazing the valve body, the core must be removed, then refitted and tightened to the correct torque |
| All Schrader cores are suitable for all refrigerants |
| Hydrocarbons leak through Schrader valves |
120
Difficult
How does an undercharge affect the high-pressure side (without discharge pressure control)?
| Discharge pressure higher, subcooling higher |
| Discharge pressure higher, subcooling lower |
| Discharge (condensing) pressure and subcooling will both be lower |
| Discharge pressure lower, subcooling higher |
121
Difficult
What is the benefit of adding helium as a tracer gas to nitrogen in a pressure test?
| It reacts with refrigerant residues, producing a visible colour change |
| Its small atoms pass easily through leaks and are detected |
| It has a distinctive odour that helps locate the leak |
| It has a higher pressure than pure nitrogen in the same cylinder |
122
Medium
Who is responsible for keeping the equipment records?
| There is no such obligation. |
| The person responsible for risk assessment. |
| The equipment maintenance technician. |
| The operator of the unit or system. |
123
Difficult
What can be the effect of a relief valve lifting repeatedly?
| The valve may not reseat tightly and its set (opening) pressure may decrease |
| The valve no longer opens |
| The valve stays fully open permanently |
| The set pressure increases |
124
Medium
Where are oil traps installed on the suction line?
| Before the safety valve on the suction side |
| At the inlet to every component of the refrigeration system |
| Immediately before the compressor suction connection |
| At the bottom of vertical suction risers with upward flow |
125
Difficult
What is the relationship between the pressure (p) and temperature (T) of nitrogen at the start (1) and end (2) of a tightness test (p absolute, T in kelvin)?
| p₂ = (p₁ × T₁)/T₂ |
| p₂ = T₁/(p₁ × T₂) |
| p₂ = T₂/(p₁ × T₁) |
| p₂ = (p₁ × T₂)/T₁ |
126
Medium
Which symptoms with the compressor running indicate a refrigerant leak (undercharge)?
| Rising condensing and suction pressures with no superheat |
| Rising liquid level in the receiver and increasing subcooling |
| Sight glass full of liquid and rising oil level in the crankcase |
| Low suction pressure, high superheat and negligible subcooling |
127
Medium
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 |
128
Medium
What pressure is used for the pressure tightness test of an installation?
| The pressure specified in EN 378-2 or by the manufacturer, not exceeding the maximum allowable pressure of the system (PS) |
| A pressure equal to the maximum pressure measured during operation |
| A pressure chosen by the technician based on experience |
| Always 30 bar |
129
Medium
At which points of the unit must the leak check be carried out?
| Only at connections of measuring instruments |
| Only on compressor shut-off valves, solenoid valves and filters |
| At all points where there is a potential risk of refrigerant leakage |
| Only on discharge-side components |
130
Medium
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 |
131
Medium
Which legal act currently sets out the obligation to check stationary refrigeration equipment containing F-gases for leaks, and how often this must be done?
| Regulation (EU) No 517/2014 |
| Regulation (EU) 2024/573 |
| Implementing Regulation (EU) 2024/2215 |
| Commission Regulation (EC) No 1516/2007 |
132
Difficult
Which parts of a refrigeration system should be given particular attention during a leak check?
| Only condenser connections, because the refrigerant is liquid there |
| Joints, valves incl. stems, seals, parts subject to vibration, connections to safety devices |
| Compressor and receiver connections, because the pressure is highest there |
| Only compressor connections, because they are the only parts subject to vibration |
133
Easy
What is the superheat of refrigerant vapour?
| The difference between the condensing temperature and the ambient temperature |
| The amount of heat required to evaporate a liquid |
| The difference between the actual vapour temperature and the saturation temperature corresponding to its pressure (expressed in K) |
| The difference between the saturation temperature and the actual liquid temperature in the liquid line |
134
Difficult
Leak checks can be carried out using various methods. Which pair is correct?
| Methods with and without quality control of supplies |
| Physical and chemical methods |
| Material quality control methods and electronic methods |
| Direct and indirect methods |
135
Difficult
To whom can leak checks of stationary refrigeration equipment containing F-gases be entrusted?
| A person who has carried out such checks before |
| Any leak-testing specialist |
| A natural person holding a certificate covering leak checks (A1, A2 within its charge limit, or E) |
| An employee appointed by the owner of the installation |
136
Difficult
What conditions must be met to use UV dye for leak checking?
| A UDT authorisation for pressure testing is required |
| Manufacturer approval of the method and a certificate covering breaking into the circuit |
| It is sufficient that introducing dye into the circuit is technically feasible |
| It is sufficient to have a UV lamp, dye and safety goggles |
137
Difficult
Which leak-checking methods are considered direct methods?
| Pressure-change measurement and immersion in water |
| Nitrogen with tracer gas and pressure measurement |
| Vacuum test and foam solution |
| 1. gas detection devices (portable or fixed leak detection system), 2. UV detection fluid or dye, 3. bubble/foam solutions |
138
Difficult
What do indirect leak-checking methods involve?
| Leak detection with an electronic detector |
| A visual and manual check and analysis of parameters: pressure, temperature, compressor current, liquid levels and recharge volume |
| Ultrasonic measurement |
| Leak detection with UV dye |
139
Medium
How should the pressure be increased during a pressure tightness test?
| As quickly as possible |
| Gradually, in stages, checking for leaks at each level until the test pressure is reached |
| In one step, by fully opening the nitrogen cylinder valve |
| In any way |
140
Medium
What electronic equipment should be used for leak checking?
| Detectors suited to the refrigerant in the system, with appropriate sensitivity, checked periodically |
| Only detectors with an infrared sensor |
| Only devices with an 'ion pump' sensor |
| Only hot-cathode devices |
141
Medium
What documentation should be checked before starting a leak check?
| Attendance sheets of the plant-room staff for the year |
| Only the installation invoice and the first start-up report |
| The operator's fixed-asset inventory ledger |
| The equipment records – especially recurring problems and previous leaks |
142
Medium
What information must be recorded in the leak check report?
| Date, number and location of leaks, how they were repaired, technician details and signature |
| The method used, the time spent on site and the cost of repair |
| The date, a general note about the leak and the operator's signature |
| Only the number of leaks found and the date of the check |
143
Medium
What pressure should be used for the pressure tightness test?
| Always 2–3 bar |
| Always 10–12 bar |
| A pressure not exceeding the maximum allowable pressure of the system (PS) |
| Any pressure, at the technician's discretion |
144
Medium
What is the temperature glide of a refrigerant?
| 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 |
| The temperature drop of the refrigerant across the expansion valve |
145
Difficult
What does a vacuum (decay) test involve?
| After isolating the pump, you check whether the system pressure rises |
| With the pump running, you watch the vacuum gauge reading |
| The pump runs continuously to hold the required vacuum for the test |
| The pump is restarted every time the system pressure rises |
146
Difficult
How often should leak tests be carried out on equipment containing 1.5 kg of R404A refrigerant (5.9 tonnes of CO₂ equivalent)?
| Only when servicing the unit. |
| Once every six months. |
| At least once every 12 months. |
| On initial commissioning. |
147
Difficult
How often should leak tests be carried out on equipment containing 7 kg of R404A refrigerant (27.45 tonnes of CO₂ equivalent)?
| On initial commissioning. |
| Once every six months. |
| Only when servicing the unit. |
| At least once every 12 months. |
148
Medium
In which equipment is a leakage detection system required?
| Equipment with 50 t CO₂ eq or more of F-gases, regardless of equipment type |
| Equipment with 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 |
149
Difficult
Under Regulation (EU) 2024/573, a leakage detection system is mandatory when:
| the equipment contains a flammable refrigerant in any quantity |
| the F-gas charge of the refrigeration equipment is 500 t CO₂ eq or more |
| the equipment operates in an enclosed space |
| the charge is 100 kg or more of ozone-depleting substances |
150
Difficult
Which leak-checking method may NOT be used by a holder of a Category E certificate?
| Checking with a foaming solution |
| Leak checking with a fluorescent dye introduced into the circuit |
| Visual inspection |
| Measurement with a handheld electronic detector |
151
Medium
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 |
152
Medium
Which certificate types (A1, A2, B, C, D, E) authorise leak checks of equipment containing F-gases?
| All except D |
| Only E |
| Only A1 and A2 |
| A1, A2 and E |
153
Difficult
Within what timeframe must a leak test be carried out on a stationary refrigeration system after a leak has been repaired, in accordance with EU Regulation 2024/573 on F-gases?
| Between 24 hours and 1 month after the repair. |
| At any time. |
| Immediately after the repair. |
| At the next periodic inspection. |
154
Difficult
How often must refrigeration equipment containing ≥500 t CO₂ eq of F-gases be checked if (contrary to Article 6) no leakage detection system is installed?
| Every 6 months |
| Every 12 months |
| Every month |
| Every 3 months |
155
Medium
Why is it advisable to subcool the liquid refrigerant?
| To ensure that liquid free of vapour bubbles enters the expansion valve |
| To lower the evaporating temperature in the evaporator |
| To allow a condenser with a smaller heat-exchange surface to be used |
| To allow a smaller expansion valve to be used |
156
Medium
What must be done after repairing a leak in the refrigeration unit of a refrigerated trailer?
| 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 |
| Issue the invoice and leave the leak check to the next periodic service |
| Visually inspect only the bolted and brazed joints near the repair |
157
Medium
Recovery of fluorinated greenhouse gases means:
| The reprocessing of fluorinated greenhouse gases to achieve their specified standard properties. |
| The reuse of fluorinated greenhouse gases following a basic purification process. |
| 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. |
158
Medium
Who is authorised to recover refrigerant from stationary refrigeration equipment containing F-gases?
| 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) |
| The administrator of the operator's account in the register |
159
Medium
How must recovered refrigerants be stored?
| In a disposable (non-refillable) cylinder that held the same refrigerant |
| In any used refrigerant cylinder, provided it is leak-tight |
| In a labelled recovery cylinder with a dual valve and a valid inspection |
| In any pressure vessel that has some form of approval |
160
Medium
When should the recovery of fluorinated greenhouse gases be carried out:
| Only prior to the final disposal of equipment. |
| Before the final disposal of equipment and, where applicable, during its servicing and maintenance. |
| Before each leak test of the equipment. |
| Always during servicing and maintenance of equipment. |
161
Medium
What should be done if recovered refrigerant is contaminated (e.g. with acid, air or moisture)?
| Hand it over to a specialised, authorised company for reclamation or destruction |
| Clean the mixture yourself using a filter-drier |
| Pass it through a particle filter and reuse it |
| Add a special contaminant neutraliser |
162
Medium
What should be done if different refrigerants have been mixed in a storage cylinder?
| Separate the mixture into its components yourself |
| Pass it through a filter-drier and reuse it |
| Hand the mixture over to an authorised company – as a rule for destruction |
| Add a special refrigerant to the mixture |
163
Medium
How does push-pull refrigerant recovery work?
| 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 |
| The recovery unit draws vapour from the system and condenses it in the cylinder |
| Nitrogen is injected into the system, pushing the refrigerant into the atmosphere |
| Refrigerant is drawn alternately from the suction and discharge sides of the compressor |
164
Medium
What are the options for managing waste refrigerant?
| Reclamation, recovery |
| Recycling, reclamation, destruction |
| Recovery, disposal |
| Disposal, storage |
165
Medium
Which management option restores recovered refrigerant to a quality equivalent to virgin product, so that it can be used by any undertaking?
| Destruction |
| Storage |
| Recycling |
| Reclamation |
166
Medium
The lower the evaporating temperature, …
| …the lower the density of the suction vapour and the lower the refrigerant mass flow rate |
| …the greater the density of the suction vapour and the greater the refrigerant mass flow rate |
| …the 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 greater the cooling capacity of the compressor |
167
Medium
How must transportable pressure vessels (e.g. refrigerant cylinders) be marked?
| With the manufacturer's logo and date of manufacture |
| Only with weight and capacity marks |
| The marking is optional |
| Among other things: the number of the design and testing standard, marks of the approving country and the inspection body, the date of the initial inspection, and the manufacturer's and operational marks |
168
Medium
The recovery of refrigerants does not require the use of:
| A refrigerant recovery station. |
| Hoses with shut-off valves. |
| Scales with a measurement range suitable for the size of the cylinder being filled. |
| An electronic leak detector. |
169
Medium
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 compresses ambient air and increases the pressure of the refrigerant. |
| The compressor condenses the refrigerant. |
| The compressor creates a vacuum on the suction side of the system |
170
Easy
What is the compression ratio of a compressor?
| The amount of refrigerant compressed per cycle relative to heat capacity |
| The ratio of discharge pressure to the effective capacity of the compressor (p/Vk) |
| The ratio of absolute discharge pressure to absolute suction pressure (pc/po) |
| The ratio of suction pressure to discharge pressure (po/pc) |
171
Medium
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 |
| Excess oil in the condenser |
| Flooding of the compressor by rainwater |
172
Medium
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) |
| By a maximum of 10% |
| From approximately 10% to 90% of nominal capacity |
| Speed control does not change the cooling capacity |
173
Easy
What is the theoretical displacement (swept volume flow) of a compressor?
| The volume of refrigerant flowing in one piston cycle under actual operating conditions |
| A value expressed by the coefficient of performance (COP) |
| The volume of a single cylinder in cm³ |
| The volume of vapour drawn in per unit of time, determined by the compressor's geometry and speed (stated by the manufacturer, e.g. in m³/h) |
174
Medium
Why is it essential to observe the correct phase sequence for scroll compressors and screw compressors?
| Because the motor speed would decrease, and consequently the compressor’s capacity. |
| Because changing the phase sequence would reverse the direction of rotation of the compressor rotors, which could result in damage to the compressors. |
| Because this type of compressor has difficulty starting up if the phase sequence is changed. |
| Because these types of compressors are sensitive to voltage drops. |
175
Medium
What compression ratio should each stage of a two-stage vapour-compression system have (rule of thumb)?
| Greater than 10 |
| Equal to 1 |
| Less than approximately 8 |
| Greater than 18 |
176
Medium
Why is a shaft seal necessary in open-type compressors?
| To protect the crankshaft bearing |
| Only to prevent oil leakage |
| To ensure the bearing remains lubricated |
| To prevent air from entering and refrigerant from leaking out of the compressor |
177
Medium
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 |
178
Medium
Why is the compressor crankcase heated?
| To dehydrate the oil |
| 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 |
179
Easy
What is the clearance (dead) volume of a reciprocating compressor?
| The volume between the valve plate and the piston crown at top dead centre |
| The space between the side of the piston and the cylinder |
| The volume between the valve plate and the piston at bottom dead centre |
| The space between the underside of the piston and the crankcase cover |
180
Medium
What are compressor packs (racks)?
| Several air-cooled condensers |
| Sets of compressors connected in any configuration |
| Units with two-stage compressors |
| Several compressors connected in parallel on a common frame with common suction and discharge headers |
181
Medium
What is the main advantage of multi-compressor packs?
| Low purchase cost and easy installation without special controls |
| No need for compressor controls and safety devices |
| Stepwise capacity matching to demand, plus redundancy |
| A smaller refrigerant charge than a single-compressor system |
182
Medium
What is meant by the operating envelope (application range) of a compressor?
| A range determined by the evaporating temperature at a given ambient temperature |
| A range determined only by the evaporating temperature |
| The permissible range of evaporating and condensing temperatures (to, tk), or the corresponding pressures, within which the compressor may operate |
| The capacity, refrigerant type and dimensions of the compressor |
183
Medium
What are the basic functions of oil in a compressor?
| Increasing the cooling capacity of the refrigerant |
| Sealing leaks that develop in the installation |
| Absorbing moisture from the refrigerant |
| Lubricating bearings and sliding surfaces, removing heat, and sealing clearances (e.g. between piston and cylinder, or rotors) |
184
Medium
What are the most effective ways of controlling compressor cooling capacity?
| Pressure control valves |
| Partially covering the evaporator |
| Changing the displacement: varying the rotational speed or unloading cylinders |
| An expansion valve |
185
Medium
What does hot-gas bypass capacity control involve?
| Part of the hot discharge gas is passed through a bypass valve to the suction side (or evaporator inlet), reducing the effective capacity |
| The compressor speed is varied |
| High-pressure liquid is injected into the suction to increase capacity |
| Bypass is not used for capacity control |
186
Medium
What is the fundamental difference between hermetic and semi-hermetic compressors?
| Both can be dismantled; they differ only in cooling capacity |
| Semi-hermetic compressors run more quietly as a complete unit |
| The semi-hermetic casing is bolted (can be opened); the hermetic one is welded |
| The semi-hermetic compressor has no motor inside the casing |
187
Medium
How does a scroll compressor work?
| 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. |
| A scroll compressor is also known as a turbo compressor. |
| It is a type of piston-type device. |
188
Medium
What physical process takes place in the evaporator?
| The refrigerant condenses |
| The secondary fluid (glycol, water) evaporates while the refrigerant condenses |
| The liquid refrigerant evaporates, absorbing heat, and the vapour is slightly superheated at the outlet |
| The refrigerant is subcooled as a liquid |
189
Medium
What is the purpose of compressor capacity control?
| To increase the condensing pressure |
| To match capacity to the condensing temperature |
| To match the cooling capacity to the current demand |
| To ensure compressor lubrication |
190
Medium
Why is inverter speed control advantageous for refrigeration compressors?
| It enables continuous, smooth control of cooling capacity |
| It increases compressor capacity above nominal at any frequency |
| Reducing the speed improves oil return to the compressor |
| It can be used with any compressor to ensure lubrication |
191
Medium
Does the suction gas temperature affect the cooling capacity of the compressor?
| No – capacity depends only on the compressor displacement |
| 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 |
192
Medium
In the case of compressor units fitted with an oil level control system, is it necessary to install the compressors at the same height?
| Only screw compressors. |
| Only scroll compressors. |
| No. |
| Yes. |
193
Medium
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. |
194
Medium
Which media most commonly absorb heat from the refrigerant in the condenser?
| Only a water–glycol mixture |
| Air or water |
| Air and CO₂ |
| Ammonia |
195
Medium
What is the function of the condenser in refrigeration systems?
| Releasing only the heat from the compressor into the surroundings |
| Releasing only the heat absorbed in the evaporator into the surroundings |
| Releasing to the environment the heat absorbed in the evaporator and the heat added during compression |
| Absorption of heat rejected in the regenerative heat exchanger |
196
Medium
If the refrigerant temperature on the high-pressure side is above its critical temperature, condensation…
| …occurs provided a special condenser is used |
| …does not occur |
| …does not depend on temperature |
| …always occurs regardless of temperature |
197
Medium
How is liquid subcooling usually achieved in a refrigeration system?
| With an additional heat exchanger using liquid nitrogen |
| With hot high-pressure vapour |
| By dissolving the refrigerant in oil |
| In the final section of the condenser (or in an additional subcooler) |
198
Medium
What is the purpose of condenser fan speed control?
| To keep the condensing pressure at the correct level |
| To disperse refrigerant in the event of a leak |
| Only to protect against exceeding the maximum condensing pressure |
| To reduce energy efficiency |
199
Medium
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 |
200
Medium
Which international treaty governs the phase-out of ozone-depleting substances (CFCs, HCFCs)?
| The UN Framework Convention on Climate Change (UNFCCC) |
| The Stockholm Convention |
| The Montreal Protocol |
| The Paris Agreement |
201
Difficult
What is the basis of the GWP values in Regulation (EU) 2024/573?
| For HFCs (Annex I) – mainly the IPCC Fourth Assessment Report (AR4); for HFOs and non-fluorinated substances (Annexes II and VI) – the Sixth Assessment Report (AR6) |
| AR4 for all substances |
| Each Member State sets its own GWP values |
| AR6 for all substances |
202
Difficult
An air conditioner (not hermetically sealed) contains 2.5 kg of R410A (GWP 2088). How often must it be checked for leaks?
| Every 6 months |
| At least every 12 months (5.22 t CO₂ eq) |
| Every 3 months |
| No checks required (below 3 kg) |
203
Difficult
When is labelled hermetically sealed equipment containing HFCs (Annex I) exempt from leak checks?
| When it contains less than 10 t CO₂ eq, and in residential buildings also when it contains less than 3 kg of F-gases |
| Never – hermetically sealed equipment is always checked |
| When it contains less than 5 t CO₂ eq |
| Always, regardless of charge |
204
Difficult
Is a chiller containing 50 kg of R1234ze(E) subject to leak checks under Regulation (EU) 2024/573?
| No – HFOs are not subject to leak checks |
| Yes – every 12 months, because its GWP is low |
| No – the threshold is 5 t CO₂ eq and 50 kg of R1234ze is below 1 t CO₂ eq |
| Yes – at least every 6 months (every 12 months with a leakage detection system) |
205
Difficult
In 2026, may an existing refrigeration installation using R404A (GWP 3922) be topped up with virgin refrigerant?
| Yes, if the equipment has a leakage detection system |
| No – only reclaimed or recycled R404A is allowed (until 1 January 2030) |
| Yes – the ban applies only to equipment ≥40 t CO₂ eq |
| Yes – bans apply only to new equipment |
206
Difficult
After 1 January 2026, may an R410A (GWP 2088) air conditioner be serviced using virgin R410A?
| No – the ban covers all HFCs |
| Yes – the servicing ban for air conditioners and heat pumps covers F-gases with GWP ≥ 2500 |
| No – the ban covers all refrigerants with GWP ≥ 750 |
| Only with reclaimed refrigerant |
207
Medium
Can HFC refrigerant recovered during a repair be put straight back into the same equipment without any cleaning (filtering/drying)?
| Yes, always |
| Yes, if the operator agrees |
| Yes, if less than 24 hours have passed |
| No – recovered F-gas may be used for filling only after it has been recycled or reclaimed |
208
Medium
Who may purchase HFCs for servicing refrigeration equipment?
| Only the equipment operator |
| Any adult |
| Any business |
| Only a person holding the relevant certificate or an undertaking employing such persons |
209
Medium
Under what condition may non-hermetically sealed split air conditioning charged with F-gas be sold to an end user?
| Only if the unit contains less than 3 kg of refrigerant |
| Unconditionally |
| When evidence is provided that installation will be carried out by a certified undertaking |
| When the user signs a statement that they will install it themselves |
210
Medium
By when must the holder of an F-gas certificate issued under Regulation (EU) No 517/2014 first complete refresher training or an evaluation process?
| By 12 March 2025 |
| By 31 December 2030 |
| Never – the certificate is valid indefinitely |
| By 12 March 2029 (and then at least every 7 years) |
211
Medium
What must the holder of a Category I certificate (Regulation 2015/2067) do to continue using it?
| Nothing – Category I automatically becomes A1 |
| Update their knowledge to the level of Certificate E |
| Apply for an extension without training |
| Update their knowledge and skills to the level of Certificate A1 (Annex I to Regulation 2024/2215) |
212
Medium
What does Certificate C under Implementing Regulation (EU) 2024/2215 authorise?
| All activities in relation to CO₂ |
| All activities in Article 2(1) in relation to ammonia (NH₃) |
| Recovery of F-gases from equipment <3 kg |
| Leak checks without breaking into the circuit |
213
Medium
May a person enrolled in a certification training course carry out certified activities?
| Yes – under the supervision of a certified person, for no more than 24 months in total |
| Yes – with no time limit, if employed by a certified company |
| No, never |
| Yes – independently, for 6 months |
214
Medium
How long must the operator keep the records of equipment subject to leak checks, if they are not kept in a national database?
| Until the equipment is decommissioned |
| At least 1 year |
| At least 5 years |
| At least 2 years |
215
Difficult
Since 1 January 2025, may a new single-split air conditioner containing 1.5 kg of R410A be placed on the market?
| Yes, if the unit is hermetically sealed |
| No – single splits <3 kg with F-gases of GWP ≥ 750 are banned |
| Yes – the ban applies from 2029 |
| Yes – the ban applies only to units >12 kW |
216
Difficult
From when is it prohibited to place on the market split air-to-air systems up to 12 kW containing F-gases with GWP ≥150 (unless required for safety)?
| From 1 January 2027 |
| From 1 January 2025 |
| From 1 January 2035 |
| From 1 January 2029 |
217
Difficult
Which persistent atmospheric degradation product of R1234yf is classed as a PFAS?
| Trifluoroacetic acid (TFA) |
| Carbon dioxide |
| Carbonic acid |
| Ozone |
218
Medium
What is floating head pressure and what does it achieve?
| 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) |
| It increases subcooling by flooding the condenser |
| It keeps a constant high condensing pressure all year |
219
Medium
How do SEER/SCOP differ from EER/COP?
| There is no difference – they are synonyms |
| EER/COP are always higher than SEER/SCOP |
| 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) |
220
Medium
Which design approach can significantly reduce the F-gas charge of a large refrigeration installation?
| An indirect (secondary-coolant) system or a cascade with a natural refrigerant in the low stage, plus heat exchangers with small internal volume |
| Omitting pipe insulation |
| Larger liquid-line diameters |
| Adding a second liquid receiver |
221
Medium
Which information must be entered in the equipment records after a leak 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 |
| Only the date of the check |
222
Medium
What must be done when an indirect method (e.g. parameter analysis) indicates a possible leak?
| Carry out a direct-method examination to locate the leak |
| Top up the refrigerant and end the check |
| Record it and check at the next periodic inspection |
| Nothing – indirect methods are sufficient |