A.insufficient cooling water flow to the condenser
B.a low refrigerant charge in the system
C.the liquid valve is open too much
D.high evaporator superheat
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A.dead band action
B.neutral zone action
C.range
D.on-off action
A.cavitation
B.electrolysis
C.abrasion
D.corrosion
A.the relief valve should open before the high pressure cutout
B.the relief valve should open and allow the excess refrigerant to flow to the receiver
C.the high pressure cutout switch should operate before the relief valve opens
D.you should close in on the suction valve
A.cause of salt contamination
B.location of salt water contamination
C.chemical makeup of feed-water
D.level of alkalinity in condensate
A.restriction in refrigerant piping
B.air and non-condensable gases in the condenser
C.water in the refrigerant
D.flooding back of liquid refrigerant from the evaporator
A.A shortage of liquid refrigerant
B.Excessive frost on the evaporator
C.Excessive condenser cooling water
D.Insufficient condenser cooling water flow
A.eliminate hot air from the condenser
B.maintain steady pressure in a system
C.heat, or cool one fluid by means of another fluid
D.reduce the engine room temperature in tropical climates
A.Cross
B.Parallel
C.Counter
D.Circular
A.remain constant along the tubes length
B.be greatest in a single pass counter flow heat exchanger
C.remain constant throughout the heat exchanger
D.vary from section to section through out the heat exchanger
A.a low load on the unit
B.a clogged pump suction strainer
C.a blockage in the line between the pump and hydraulic motor
D.the hydraulic motor turning too fast
最新试题
Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by （）.
An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.
A salinity indicator is used to determine the （）.
Low compressor head pressure in a refrigeration system can be caused by（）.
An internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of （）.
If the head pressure of a reciprocating refrigeration compressor is excessive, （）.
On tank vessels equipped with power operated cargo tank valves, the type of power operator most commonly used is （）.
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.
A salinity indicator is used to determine the （）.
The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.