Refrigeration Final Exam Questions with
Latest Update
A hot pull down occurs when:
a) there is excessive ice on the evaporator
b) the condenser has been flooded
c) the metering device is starving the evaporator
d) the temperature of the load is high and the compressor has to run for long periods of
time to lower the load
d) all of the above - Answer-d)
The receiver is located in the: - Answer-Liquid line
The solenoid valve is used to control fluid flow. This valve:
a) has a slow reaction time
b) has a fast or snap action
c) is used to control fan speed
d) is usually normally open in most refrigeration applications - Answer-b)
An EEPR valve uses a sensor in the refrigerated cases's:
a) return air
b) discharge air
c) evaporator outlet
d) evaporator inlet
e) none of the above - Answer-b)
A tech must_________________ the suction service vale before removing the gauge
hose when service is complete
a) Front seat
b) Back seat
c) Mid seat
d) Crack - Answer-b)
What is the purpose of installing a crank case heater? - Answer-To ensure liquid
refrigerant does not migrate during low ambient
What valve is located on the outlet of the receiver? - Answer-king valve
At what location in a regrigeration sytem would a tech install an oil sperator? (in
between what 2 mojor components) - Answer-compressor and condenser
to protect the compressor from damage when refrigerant loss occurs due to a large
leak, a _____________ switch should be installed - Answer-pressure
,a CPR valve________ on rise of_____ presure - Answer-close/ outlet
an EPR valve ____________ on rise of _________ pressure - Answer-opens/ inlet
Why would a tech incorporate EPR valves into a refrigeration system? - Answer-Multiple
temperature and multiple evaporators
The entire refrigerant charge of a system should only fill what percentage of the
receiver?
a) 50%
b) 60%
c) 80%
d) 100%
e) 110% - Answer-c)
What type of valve can be installed between the receiver and the pressure relief
valve(s)?
a) ball valve
b) gate valve
c) three-way valve
d) emergency valve
e) no valve - Answer-c)
2 types of pressure relief valves found on refrigeration systems: - Answer-spring valve
one time
How does a pilot perated liguid line solenoid valve operate? - Answer-Signal sent for
system pressure to start and stop flow
Air conditioning systems:
a) initiate defrost with a defrost clock
b) initiate defrost with a pressure switch
c) defrost during off cycle when the thermostat is satisfied
d) do not require defrost - Answer-d)
A low pressure switch will________ on rise in pressure - Answer-close
A high pressure safety switch will ______ on rise in head pressure - Answer-open
A fan cycling switch will _______ on rise in head pressure - Answer-close
When the box temperature is satisfied, the thermostat contacts on the thermostat
will_______ - Answer-open
Dampers for a condenser will ______ during low ambient conditions - Answer-close
, In an automatic pump-down system, the thermostat controls the ________ operation -
Answer-solenoid valve
In an automatic pump-down system, the pressure controller will control the ______
operation - Answer-compressor
Random defrost is accomplished:
a) with a timer
b) using the high pressure control
c) using the low pressure control
d) during normal off cycle when the box is satisfied - Answer-d)
During electric defrost in a freezer:
a) the compressor and the evaporator fans would be off
b) the electric heaters and the compressor would be on
c) the electric heaters and the compressor would be on
d) all of the above are possible - Answer-a)
Superheat is:
a) the heat of compression at the compressor
b) latent heat given off by the condenser
c) sensible heat absorbed by the refrigerant after it has boiled to vapor
d) heat used to boil the liquid in the evaporator - Answer-c)
A metering device is degined to:
a) lower the boiling point of the refrigerant after it has boiled to vapor
b) regulate the flow of refrigerant into the evaporator
c) produce a reduction in pressure on the liquidrefrigerant
d) all of the above - Answer-d)
A thermostatic expansion valve controls refrigerant flow to the evaporator based on:
a) rate of liquid vaporization
b) external equalizer pressure
c) evaporator suction line super heat
d) all of the above - Answer-c)
A small amount of superheat in the suction line is desirable with a TXV to:
a) keep the proper amount of refrigerant in the receiver
b) ensure that no liquid refrigerant enters the compressor
c) keep from starving the evaporator
d) super heat is not desirable in the suction line - Answer-b)
When the load on the evaporator increases, the TXV will:
a) decrease the pressure drop across the evaporator
b) increase the flow of refrigerant
c) decrease the flow of refrigerant
Latest Update
A hot pull down occurs when:
a) there is excessive ice on the evaporator
b) the condenser has been flooded
c) the metering device is starving the evaporator
d) the temperature of the load is high and the compressor has to run for long periods of
time to lower the load
d) all of the above - Answer-d)
The receiver is located in the: - Answer-Liquid line
The solenoid valve is used to control fluid flow. This valve:
a) has a slow reaction time
b) has a fast or snap action
c) is used to control fan speed
d) is usually normally open in most refrigeration applications - Answer-b)
An EEPR valve uses a sensor in the refrigerated cases's:
a) return air
b) discharge air
c) evaporator outlet
d) evaporator inlet
e) none of the above - Answer-b)
A tech must_________________ the suction service vale before removing the gauge
hose when service is complete
a) Front seat
b) Back seat
c) Mid seat
d) Crack - Answer-b)
What is the purpose of installing a crank case heater? - Answer-To ensure liquid
refrigerant does not migrate during low ambient
What valve is located on the outlet of the receiver? - Answer-king valve
At what location in a regrigeration sytem would a tech install an oil sperator? (in
between what 2 mojor components) - Answer-compressor and condenser
to protect the compressor from damage when refrigerant loss occurs due to a large
leak, a _____________ switch should be installed - Answer-pressure
,a CPR valve________ on rise of_____ presure - Answer-close/ outlet
an EPR valve ____________ on rise of _________ pressure - Answer-opens/ inlet
Why would a tech incorporate EPR valves into a refrigeration system? - Answer-Multiple
temperature and multiple evaporators
The entire refrigerant charge of a system should only fill what percentage of the
receiver?
a) 50%
b) 60%
c) 80%
d) 100%
e) 110% - Answer-c)
What type of valve can be installed between the receiver and the pressure relief
valve(s)?
a) ball valve
b) gate valve
c) three-way valve
d) emergency valve
e) no valve - Answer-c)
2 types of pressure relief valves found on refrigeration systems: - Answer-spring valve
one time
How does a pilot perated liguid line solenoid valve operate? - Answer-Signal sent for
system pressure to start and stop flow
Air conditioning systems:
a) initiate defrost with a defrost clock
b) initiate defrost with a pressure switch
c) defrost during off cycle when the thermostat is satisfied
d) do not require defrost - Answer-d)
A low pressure switch will________ on rise in pressure - Answer-close
A high pressure safety switch will ______ on rise in head pressure - Answer-open
A fan cycling switch will _______ on rise in head pressure - Answer-close
When the box temperature is satisfied, the thermostat contacts on the thermostat
will_______ - Answer-open
Dampers for a condenser will ______ during low ambient conditions - Answer-close
, In an automatic pump-down system, the thermostat controls the ________ operation -
Answer-solenoid valve
In an automatic pump-down system, the pressure controller will control the ______
operation - Answer-compressor
Random defrost is accomplished:
a) with a timer
b) using the high pressure control
c) using the low pressure control
d) during normal off cycle when the box is satisfied - Answer-d)
During electric defrost in a freezer:
a) the compressor and the evaporator fans would be off
b) the electric heaters and the compressor would be on
c) the electric heaters and the compressor would be on
d) all of the above are possible - Answer-a)
Superheat is:
a) the heat of compression at the compressor
b) latent heat given off by the condenser
c) sensible heat absorbed by the refrigerant after it has boiled to vapor
d) heat used to boil the liquid in the evaporator - Answer-c)
A metering device is degined to:
a) lower the boiling point of the refrigerant after it has boiled to vapor
b) regulate the flow of refrigerant into the evaporator
c) produce a reduction in pressure on the liquidrefrigerant
d) all of the above - Answer-d)
A thermostatic expansion valve controls refrigerant flow to the evaporator based on:
a) rate of liquid vaporization
b) external equalizer pressure
c) evaporator suction line super heat
d) all of the above - Answer-c)
A small amount of superheat in the suction line is desirable with a TXV to:
a) keep the proper amount of refrigerant in the receiver
b) ensure that no liquid refrigerant enters the compressor
c) keep from starving the evaporator
d) super heat is not desirable in the suction line - Answer-b)
When the load on the evaporator increases, the TXV will:
a) decrease the pressure drop across the evaporator
b) increase the flow of refrigerant
c) decrease the flow of refrigerant
