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单选题
The compressor in an air-cooled condensing refrigeration system is short cycling on the high pressure cutout switch（）
A
system is overcharged with refrigerant
B
system is low on refrigerant
C
discharge valves are leaking excessively
D
discharge valves are leaking slightly
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higher than normal head pressureC
a clear sight glassD
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单选题When a refrigeration compressor is in the ‘off’ cycle, the thermal expansion valve will（）.A
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单选题An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.A
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humidityB
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单选题Which of the following may cause that the compressor cuts off on high pressure cutout in a refrigeration plant? （） (1) faulty condensing (2) too few refrigerant (3) high discharge pressureA
any of (1) and (3)B
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考题
单选题The purpose of the refrigeration system low pressure cutout switch is to （）A
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protect the compressor from low discharge pressureC
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考题
单选题Sweating of the refrigeration system compressor crankcase is caused by （）.A
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单选题Excessive oil foaming in the crankcase of a refrigeration compressor is most likely to occur（） when the compressor.A
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单选题The presence of bubbles in a refrigeration system liquid line may （）.A
promote refrigerant dehydrationB
be absorbed in the receiverC
cause low condensing pressureD
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