A.have a greater head capacity
B.operate with increased impeller efficiency
C.discharge through the suction side of the pump casing
D.require more power to run the shaft
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A.hydraulic fluid contamination
B.excessive fluid friction
C.turbulent fluid flow
D.fluid pressure surges
A.yearly
B.quarterly
C.monthly
D.daily
A.evaporator pressure decrease
B.evaporator coil over-feed
C.evaporator capacity increase
D.expansion valve diaphragm rupture
A.head capacity to improve
B.discharge to be reversed
C.efficiency to decrease
D.slippage to decrease
A.gums, acids, and varnishes
B.removed by cellulose type filters
C.neutralized by oil additives
D.not removed by absorbent filters
最新試題
Low compressor head pressure in a refrigeration system can be caused by（）.
Thermostatic expansion valves can be adjusted for （）.
Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by （）.
The general purpose of a heat exchanger is to （）.
The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.
When the steering gear is in operation, you should （）.
A salinity indicator is used to determine the （）.
A gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.
The rate of heat transfer from a hot region to a cold region is affected most by the （）.
When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.