If a refrigeration compressor were short cycling on the low pressure cutout switch, the probable cause for this might be the （）.

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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 is short cycling on high head pressure, you should （）.

  A . purge the condenser if the waterside is dirty B . check for proper water flow through the condenser C . increase the high pressure cutout setting D . reduce the cooling water flow

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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

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