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Low compressor head pressure in a refrigeration system can be caused by ___.
A.insufficient condenser cooling water
B.excessive condenser cooling water
C.air in the refrigeration system
D.excessive refrigerant in the system
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更多 “ Low compressor head pressure in a refrigeration system can be caused by ___.A.insufficient condenser cooling waterB.excessive condenser cooling waterC.air in the refrigeration systemD.excessive refrigerant in the system ” 相关考题
考题
Which of the conditions listed will cause a refrigeration compressor to run constantly without simultaneously decreasing the temperature in the refrigerated space?( )A.Shortage of refrigerant oilB.Slight shortage of refrigerantC.Excessive condenser cooling water flowD.Faulty expansion valve
考题
If a refrigeration compressor is short cycling on high head pressure, you shouldA.purge the condenser if the waterside is dirtyB.check for proper water flow through the condenserC.increase the high pressure cutout settingD.reduce the cooling water flow
考题
In the refrigeration system, a shortage of refrigerant is indicated byA.the compressor short cycling on high pressure cut out switchB.high suction pressureC.high head pressureD.bubbles in the sight glass
考题
Sweating of the refrigeration system compressor crankcase is caused by_______ .A.too much superheatB.insufficient superheatC.suction pressure too lowD.excessive refrigerant returning to the compressor
考题
Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?A.A shortage of liquid refrigerant.B.Excessive frost on the evaporator.C.Excessive condenser cooling water.D.Insufficient condenser cooling water flow.
考题
单选题Low compressor head pressure in a refrigeration system can be caused by（）.A
insufficient condenser cooling waterB
excessive condenser cooling waterC
air in the refrigeration systemD
excessive refrigerant in the system
考题
单选题The presence of air in the condenser of a refrigeration system will （） the condensing pressure.A
increaseB
reduceC
maintain constantD
None of the above is true
考题
单选题If a refrigeration compressor is running continuously without lowering the temperature in the refrigerated space, the trouble may be （）.A
a shortage of compressor oilB
warm food in the refrigeratorC
excessive condenser cooling waterD
a shortage of refrigerant
考题
单选题Which of the conditions listed will cause a refrigeration compressor to run constantly without simultaneously decreasing the temperature in the refrigerated space?（）A
Shortage of refrigerant oilB
Slight shortage of refrigerantC
Excessive condenser cooling water flowD
Faulty expansion valve
考题
单选题An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.A
restriction in refrigerant pipingB
air and non-condensable gases in the condenserC
water in the refrigerantD
flooding back of liquid refrigerant from the evaporator
考题
单选题Which of the following terms represents the form of heat removed from the refrigerant in the condenser of a refrigeration system?（）A
Latent heat of vaporizationB
Heat of compressionC
SuperheatD
All of the above
考题
单选题In a compression refrigeration plant the refrigerant is under low pressure in the （） and under high pressure in the （）.A
compressor；condenserB
condenser；evaporatorC
throttle valve；evaporatorD
evaporator；condenser
考题
单选题If the high-pressure switch on the compressor opens and stops the compressor a possible cause could be:（）A
too much cooling water going through the condenserB
not enough refrigerant in the systemC
a leak in the evaporator coilsD
no enough cooling water going through the condenser
考题
单选题When adding oil to a refrigeration system, precautions must be taken to ensure that （）.A
the compressor suction pressure is not too highB
all air is purged from the pump and charging fittingsC
the high pressure cutout switch is held open to prevent accidental startingD
the condenser is completely shutdown first
考题
单选题If a refrigeration compressor is short cycling on high head pressure, you should （）.A
purge the condenser if the waterside is dirtyB
check for proper water flow through the condenserC
increase the high pressure cutout settingD
reduce the cooling water flow
考题
单选题While troubleshooting a refrigeration system for low head pressure, liquid refrigerant flooding back from the evaporator is determined to be the causeIt may be necessary to （）.A
change the expansion valve adjustmentB
readjust the water regulating valve to increase the flow of waterC
purge air from the condenserD
clean the waterside of the condenser
考题
单选题One cause of high head pressure occurring in a refrigeration system can be （）.A
insufficient cooling water flow to the condenserB
a low refrigerant charge in the systemC
the liquid valve is open too muchD
high evaporator superheat
考题
单选题The purpose of the refrigeration system low pressure cutout switch is to （）A
protect the compressor from liquid flood backB
protect the compressor from low discharge pressureC
start and stop the compressor upon system demandD
start the compressor after a drop in the evaporator pressure
考题
单选题Sweating of the refrigeration system compressor crankcase is caused by （）.A
too much superheatB
insufficient superheatC
suction pressure too lowD
excessive refrigerant returning to the compressor
考题
单选题In a refrigeration system, if the cooling water to the condenser fails, the（）.A
box temperature solenoid valve will closeB
expansion valve will closeC
compressor will shutdownD
king valve will open
考题
单选题Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?（）A
A shortage of liquid refrigerantB
Excessive frost on the evaporatorC
Excessive condenser cooling waterD
Insufficient condenser cooling water flow
考题
单选题Which will cause the high pressure cutout to stop the compressor in a R-22 system?（）A
Condenser leakageB
A shortage of liquid refrigerantC
Excessive frost on the evaporatorD
Not enough condenser cooling water
考题
单选题When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.A
increase the amount of cooling water to the condenserB
decrease the amount of cooling water to the condenserC
add more refrigerant to the systemD
remove some refrigerant from the system
考题
单选题In the refrigeration system, a shortage of refrigerant is indicated by （）.A
the compressor short cycling on high pressure cut out switchB
high suction pressureC
high head pressureD
bubbles in the sight glass
考题
单选题Refrigerant is normally sub-cooled in a refrigeration or air conditioning system condenser to （）.A
maintain adequate coil back pressureB
prohibit flashing in the liquid lineC
reduce refrigerant volume in the systemD
reduce compressor discharge line loading
考题
单选题Which of the listed components is considered to separate the high pressure side of a refrigeration cycle from the low pressure side of the cycle?（）A
The condenser and the expansion valveB
The king valve and the solenoid valveC
The compressor and the expansion valveD
The condenser and the solenoid valve
考题
单选题If a refrigeration compressor is running continuously without lowering temperature as normal in the refrigerator, the trouble may be （）.A
excessive condenser cooling waterB
warm food in the refrigeratorC
a shortage of refrigerantD
s shortage of compressor oil
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