F-Gas Exam

Question 1

What best describes enthalpy?

Answer 1

Heat content per unit mass - KJ/Kg

Question 2

What is the function of an evaporative condenser?

Answer 2

To reject latent heat to change vapour to liquid

Question 3

What will provide the sight glass with a clear liquid line?

Answer 3

Sub-cooled liquid

Question 4

What does the Kyoto protocol cover?

Answer 4

Climate Change

Question 5

What refrigerant is most likely to suffer from changes in its composition after leakage?

Answer 5

R407c - Zeotrope Refrigerant blend

Question 6

Energy efficient ration of a heat pump system is?

Answer 6

Heating capacity over Total system input power

Question 7

As the difference between condensing temperature decreases what happens?

Answer 7

Work done decreases and discharge temperature decreases

Question 8

What qualification is required to recover refrigerant from an A/C system which has a charge of 7.5kg of R407c

Answer 8

F Gas Qualification 1

Question 9

BS EN 378 Requires the saturation temperature of what?

Answer 9

55 Degrees

Question 10

What is most likely to increase refrigerant leakage potential from an air to water heat pump?

Answer 10

Excessive discharge vapour superheat

Question 11

The function of the compressor is what?

Answer 11

To circulate refrigerant vapour and increase pressure

Question 12

Compressor being too hot to touch on a blast freeze system indicates what?

Answer 12

Motor failure

Question 13

What would run with the lowest condensing temperature?

Answer 13

Evaporative condenser

Question 14

A Clean condenser on an A/C System leads to what?

Answer 14

A Lower discharge pressure and higher efficiency

Question 15

When every one degrees celsius that the evaporating temperature is increased….

Answer 15

Cooling capacity is increased by 3% and energy use decreased by 3%

Question 16

What is most likely to cause the evaporator of an unprotected water chiller to freeze solid?

Answer 16

Lower than normal waterside temperature

Question 17

What is the function of an expansion valve?

Answer 17

To control refrigerant flow and decrease pressure

Question 18

What setting is most likely to cause a system hermetic compressor to run continuously and over heat?

Answer 18

20K Thermostatic Expansion Valve superheat setting

Question 19

R22 is classified as a what?

Answer 19

Ozone depleting substance

Question 20

Montreal protocol is the international agreement responsible for what?

Answer 20

The phase out of HCFC’s (hydro-chloro-fluoro-carbon)

Question 21

What is the refrigerant hazard that can make an affected person feel ‘high’?

Answer 21

Central Nervous System effect

Question 22

Why must residual flux be removed from the outside of a brazed copper pipe?

Answer 22

Because it absorbs water from the air and corrodes the pipe.

Question 23

What pipe diameter is the most likely to fail when strength tested with OFN?

Answer 23

4 1/8

Question 24

GWP of R4O4a

Answer 24

3922

Question 25

GWP of R410a

Answer 25

2088

Question 26

GWP of R22

Answer 26

1810

Question 27

GWP of R245 fa

Answer 27

1030

Question 28

GWP of R123

Answer 28

120

Question 29

GWP of R600a / R290

Answer 29

3

Question 30

GWP of HF01234 yf

Answer 30

4

Question 31

GWP of R717 (Ammonia)

Answer 31

0

Question 32

Condensing, Compression, Evaporation then?

Answer 32

Expansion

Question 33

COP =

Answer 33

Refrigeration effect over Compressor work done

Question 34

EER Cooling

Answer 34

total cooling capacity over total system power input

Question 35

EER Heating

Answer 35

total heating capacity over total system power input

Question 36

Subcooling is established when?

Answer 36

Refrigerant liquid is cooled below its boiling point

Question 37

An A/C System with a pipe run of 40% of its max pre charge will have refrigerant in what state in the suction line accumulator?

Answer 37

Saturated two phase mixture

Question 38

What would allow an engineer to connect refrigerant gauges to a system with minimum refrigerant loss?

Answer 38

Service valve back seated

Question 39

What is the purpose of a TEV (Thermostatic Expansion Valve)

Answer 39

To maintain a constant superheat

Question 40

A System with a capillary tube restrictor will?

Answer 40

Allow pressures to equalise in off cycle

Question 41

A Clear sight glass and high superheat would indicate what?

Answer 41

The TEV is undersized

Question 42

TEV Bulb which has come adrift from the suction line will have what effect

Answer 42

Decrease superheat

Question 43

What direction is the most desirable for mounting a condensing unit?

Answer 43

North Facing

Question 44

The montreal protocol deals with?

Answer 44

Ozone Depletion

Question 45

E.C. Regulation 2037/2000 relates to?

Answer 45

CFC's and HCFC's

Question 46

What refrigerant is subject to controls in relation to E.C. Regulation 2037/2000

Answer 46

R22 - HCFC

Question 47

What poses the greatest risk of fire?

Answer 47

HC - Hydrocarbon

Question 48

When the MAP pressure for a refrigerant is 34 Bar what is the safest regulator to use for strength testing?

Answer 48

50 Bar - MAP X by 1.43

Question 49

The purpose of a vac pump is to?

Answer 49

1 - Evacuate the system of non - condensables 2- Reduce the pressure in the pipework below atmospheric pressure 3- To Cause moisture to evaporate

Question 50

The state of the refrigerant leaving a capillary tube restrictor/expansion device entering an evaporator would be?

Answer 50

Saturated mixture at low temperature and low pressure

Question 51

A Superheated vapour is

Answer 51

Heated above its Saturated temperature

Question 52

A change of state with no change of temperature is called?

Answer 52

Latent

Question 53

A Change of temperature with no change of state is called?

Answer 53

Sensible

Question 54

If heat is added to a saturated liquid what will be the effect?

Answer 54

It starts to boil to a vapour

Question 55

What should you vacuum a system down to?

Answer 55

2000 microns

Question 56

To keep the condenser pressure within manufacturers guidelines you should?

Answer 56

Reduce fan speed on high pressure

Question 57

Which compressor is least likely to leak?

Answer 57

Hermetic

Question 58

Which cleaning method is most damaging to a fin-coil condenser?

Answer 58

Acid-based cleaner

Question 59

GWP of R32

Answer 59

675

Question 60

GWP of R1234 ze

Answer 60

6