Noise in a refrigeration compressor can be caused by （）.

A . stores liquid refrigerant B . collects non-condensable gases C . allows refrigerant sub-cooling D . prevents compressor surging

A . refrigerant boiling out of solution from the lube oil B . liquid refrigerant flooding the compressor and system C . lube oil viscosity being reduced by refrigerant dilution D . compressor suction pressure suddenly increasing

A . the compressor short cycling on high pressure cut out switch B . high suction pressure C . high head pressure D . bubbles in the sight gla

A . higher boiling temperature for a given pressure than does a pure refrigerant B . lower boiling temperature for a given pressure than does a pure refrigerant C . boiling pressure equal to that of a pure refrigerant at a given pressure D . boiling point will not be affected by entrained oil

A . compressor B . condenser C . receiver D . evaporator

A . overheated compressor bearings B . excess lube oil viscosity C . carbon deposits on the compressor piston rings D . wax crystals forming in the lubricant

A . increased capacity of the compressor B . more efficient operation of the thermal expansion valve C . decreased capacity of the compressor D . loss of receiver capacity

A . high discharge pressure B . frosting of the crankcase C . high temperature of the overboard water D . low suction pressure of compressor

A . a stuck solenoid valve B . a shortage of refrigerant C . too much oil in circulation D . too much superheat

A . Sub-cooled liquid B . Sub-cooled vapor C . Superheated vapor D . Liquid

A . have a high viscosity index B . mix readily with refrigerant C . have a high freezing point D . have a low pour point

A . compressor；condenser B . condenser；evaporator C . throttle valve；evaporator D . evaporator；condenser

A . promote refrigerant dehydration B . be absorbed in the receiver C . cause low condensing pressure D . carry moisture and lead to corrosio

A . condenser B . vapor generator C . accumulator D . evaporator

A . evaporator B . compressor C . expansion valve D . condenser

A . increasing refrigerant pressure in the coil B . increasing chilled water flow through the cooler C . sub-cooling the refrigerant in the condenser D . superheating the refrigerant in the compressor

A . excessive condenser cooling water B . warm food in the refrigerator C . a shortage of refrigerant D . s shortage of compressor oil

A . be clear B . be blue C . be light green D . show bubble

A . evaporator B . condenser C . expansion valve D . compressor

A . with the axis of the solenoid horizontal, sensing temperature of the box, and upstream of the thermal expansion valve B . upright, sensing temperature of the box, and upstream of the thermal expansion valve C . upright, sensing temperature of the box, and downstream of the thermal expansion valve D . upright, sensing heat of the tail coil, and upstream of the thermal expansion valve

A . filter B . filter drier C . heat exchanger D . air cooler

A . the solenoid valve to seize B . the compressor to hunt C . flash gas to form in the liquid line D . the expansion valve to freeze ope

A.carbon deposits on the compressor suction valves B.the evaporator temperature to increase C.rapid corrosion of the thermal expansion valve D.no operating problems