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If the head pressure of a reciprocating refrigeration compressor is excessive, ().
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
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In a refrigeration system, if the cooling water to the condenser fails, the().
A . box temperature solenoid valve will close
B . expansion valve will close
C . compressor will shutdown
D . king valve will ope
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When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should ().
A . increase the amount of cooling water to the condenser
B . decrease the amount of cooling water to the condenser
C . add more refrigerant to the system
D . remove some refrigerant from the system
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If a refrigeration compressor will not start, the reason may be ().
A . the pressure regulating valve is not closing
B . an excessive lack of refrigerant in the system
C . badly leaking discharge valves
D . worn piston ring
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In the refrigeration system, a shortage of refrigerant is indicated by ().
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
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A refrigerant with oil in solution has a ().
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
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Before charging a refrigeration unit, the refrigerant charging lines should be()
A . flushed with clean refrigerant oil
B . purged with the refrigerant
C . washed with an ammonia and alcohol solution
D . grounded to compressor
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In a refrigeration system, the refrigerant absorbs the latent heat of vaporization in the().
A . compressor
B . condenser
C . receiver
D . evaporator
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If a refrigeration compressor were short cycling on the low pressure cutout switch, the probable cause for this might be the ().
A . system was overcharged with refrigerant
B . high pressure switch was improperly adjusted
C . expansion valve strainers were fouled
D . suction valves were leaking slightly
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Insufficient refrigerant in a refrigeration plant may result in ().
A . high discharge pressure
B . frosting of the crankcase
C . high temperature of the overboard water
D . low suction pressure of compressor
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If the refrigeration compressor crankcase is sweating, the cause may be due to ().
A . a shortage of refrigerant
B . the compressor running continuously
C . liquid refrigerant returning to the compressor
D . the compressor short cycling on the high pressure cutout
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Refrigerant entering the compressor of a refrigeration system should be in which of the following conditions?()
A . Sub-cooled liquid
B . Sub-cooled vapor
C . Superheated vapor
D . Liquid
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If a large difference exists between the compressor discharge pressure and the pressure corresponding to the existing condensing temperature in a refrigeration system, you should().
A . increase the flow of the cooling water through the condenser
B . adjust the high pressure cutout to maintain the desired pressure
C . open the hot gas bypass temporarily to reduce capacity
D . purge non-condensable gases to reduce the excess pressure
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Which of the problems listed could be indicated if a sight glass in the refrigerant liquid line is full of bubbles?()
A . Proper refrigerant charge
B . Faulty expansion valve
C . Insufficient refrigerant
D . Solenoid valve stuck ope
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If the suction pressure at the refrigeration compressor is below normal, the cause can be().
A . refrigerant overcharge
B . overfeeding by the expansion valve
C . a restricted suction strainer
D . due to short cycling of the compressor
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In a chilled water air conditioning unit using a reciprocating compressor, the refrigerating effect of the primary refrigerant can be increased by ().
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
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If a refrigeration compressor is running continuously without lowering temperature as normal in the refrigerator, the trouble may be ().
A . excessive condenser cooling water
B . warm food in the refrigerator
C . a shortage of refrigerant
D . s shortage of compressor oil
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In an operating refrigeration system low on refrigerant, a liquid line sight glass will()
A . be clear
B . be blue
C . be light green
D . show bubble
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If liquid refrigerant accidentally comes in contact with the eyes, () immediately.
A . rub the eyes
B . irritate the eyes
C . wash the eyes with a heavy boric acid solution
D . obtain medical hel
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If a liquid sight flow indicator in a refrigeration system shows gas bubbles in motion passing inside of the glass, there is ().
A . too much refrigerant in the system
B . oil entrained in the refrigerant
C . less than a full charge of refrigerant in the system
D . ice crystals forming in the refrigerant
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If a refrigeration crankcase compressor were short cycling on the low pressure cutout switch, the cause might be that the ().
A . system was overcharged with refrigerant
B . system was low on refrigerant
C . suction valves were leaking slightly
D . relief valve was leaking slightly
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Some chloronated flourocarbon refrigerants may decompose into a toxic irritating gas if it is ().
A . stored at temperatures below 60 degrees Fahrenheit
B . charged into a system having copper fittings
C . allowed to mix with compressor oil
D . exposed to an open flame or hot surface
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Refrigerant enters the condenser as a ().
A . high pressure liquid
B . low pressure vapor
C . high pressure vapor
D . low pressure liquid
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If you don’t put the milk in the refrigerator,it may__________ .
A.go by
B.go off
C.go on
D.go back