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?()