海船船员考试
单选题When a refrigeration compressor is in the ‘off’ cycle, the thermal expansion valve will（）.A always be wide open when the compressor restartsB continue to operate as if the system were in operationC remain open until evaporator pressure equalizes, then
题目
always be wide open when the compressor restarts
continue to operate as if the system were in operation
remain open until evaporator pressure equalizes, then close until the compressor restarts
always be completely closed until the compressor restarts
相似问题和答案
第1题：
Excessive oil foaming in the crankcase of a refrigeration compressor is most likely to occur when the compressor
A.has run continuously for a long period
B.suction pressure is below normal
C.oil level is below normal
D.starts after a long idle period
第2题：
If the suction pressure for an operating refrigeration compressor is below normal, the cause may be ______.
A.an excess of liquid refrigerant
B.the expansion valve overfeeding
C.a fouled compressor suction strainer
D.the compressor short cycling
第3题：
If the refrigeration compressor crankcase is sweating, the cause may be due to
A.a shortage of refrigerant
B.the compressor running continuously
C.liquid refrigerant returning to the compressor
D.the compressor short cycling on the high pressure cutout
第4题：
overheated compressor bearings
excess lube oil viscosity
carbon deposits on the compressor piston rings
wax crystals forming in the lubricant
第5题：
pressurestat
high pressure cutout
solenoid valve
low pressure cutout switch
第6题：
Sweating of the refrigeration system compressor crankcase is caused by_______ .
A.too much superheat
B.insufficient superheat
C.suction pressure too low
D.excessive refrigerant returning to the compressor
第7题：
insufficient condenser cooling water
excessive condenser cooling water
air in the refrigeration system
excessive refrigerant in the system
第8题：
When adding oil to a refrigeration system, precautions must be taken to ensure that
A.the compressor suction pressure is not too high
B.all air is purged from the pump and charging fittings
C.the high pressure cutout switch is held open to prevent accidental starting
D.the condenser is completely shutdown first
第9题：
flooding back
superheating
overflowing
recycling
第10题：
the compressor suction pressure is not too high
all air is purged from the pump and charging fittings
the high pressure cutout switch is held open to prevent accidental starting
the condenser is completely shutdown first