insufficient lube oil circulating through the system
excessive circulation of lube oil through the system
insufficient refrigerant in the system
an overworked compressor
第1题：
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
第2题：
The sensing line for the low pressure cutout switch to a refrigeration system is located ______.
A.in the chill box(冰箱)
B.before the receiver
C.on the suction side of the compressor
D.on the discharge side of the compressor
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：
flooding back
superheating
overflowing
recycling
第5题：
sudden evaporation of wax crystals in the lubricant
sudden evaporation of entrapped air in the lubricant
release of refrigerant from the oil/refrigerant mixture
release of dissolved lubricant from the refrigerant
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：
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9题：
a shortage of refrigerant in the system
air in the system
an accumulation of liquid refrigerant in the crankcase
a shortage of oil in the crankcase
第10题：
add refrigerant to the system
adjust the thermal expansion valve to the proper setting
adjust the float valve to the proper holding pressure
open the hand expansion valve