improper adjustment of the bypass valve
a dribble in the fuel injection nozzle
insufficient leak-off through injection nozzle packing
a malfunctioning injection nozzle
第1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2题：
If a diesel engine turned over freely but failed to start, the cause could be ________.
A.water in the fuel
B.cold lube oil
C.excessive starting air pressure
D.excessive fuel pressure
第3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4题：
（） is a system of unitized multimodal land transportation of transport by road and rail.
第5题：
An increase in the heat load to a refrigeration system will cause ______.
A.the suction pressure to decrease
B.the suction temperature to increase
C.increased ice formation on the evaporator coil
D.excessive short cycling of the compressor
第6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.
第7题：
If a centrifugal pump is driven by a constant speed electric motor and produces a discharge pressure less than designed, the cause is probably ______.
A.excessive pump speed
B.excessive suction head
C.worn wearing rings
D.gross pump misalignment
第8题：
Air trapped in the hydraulic fluid of a steering system may be indicated by
A.the steering pumps overspeeding
B.a jammed open relief valve
C.a constantly occurring improper rudder response
D.excessive ram pressure
第9题：
Restrictions occurring in the small orifices(孔) of pneumatic control system components can be caused by ______.
A.moisture in the compressed air supply
B.excessive dryness in the compressed air supply
C.pressure surging in the compressed air receiver
D.insufficient lubrication of the system components
第10题：
Which of the following is the MOST common problem that occurs in server rooms？（）