Low compressor head pressure in a refrigeration system can be caused by ___.A.insufficient condenser cooling waterB.excessive condenser cooling waterC.air in the refrigeration systemD.excessive refrigerant in the system
Low compressor head pressure in a refrigeration system can be caused by ___.
A.insufficient condenser cooling water
B.excessive condenser cooling water
C.air in the refrigeration system
D.excessive refrigerant in the system
相关考题：
Which of the conditions listed will cause a refrigeration compressor to run constantly without simultaneously decreasing the temperature in the refrigerated space?( )A.Shortage of refrigerant oilB.Slight shortage of refrigerantC.Excessive condenser cooling water flowD.Faulty expansion valve
If a refrigeration compressor is short cycling on high head pressure, you shouldA.purge the condenser if the waterside is dirtyB.check for proper water flow through the condenserC.increase the high pressure cutout settingD.reduce the cooling water flow
In the refrigeration system, a shortage of refrigerant is indicated byA.the compressor short cycling on high pressure cut out switchB.high suction pressureC.high head pressureD.bubbles in the sight glass
Sweating of the refrigeration system compressor crankcase is caused by_______ .A.too much superheatB.insufficient superheatC.suction pressure too lowD.excessive refrigerant returning to the compressor
Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?A.A shortage of liquid refrigerant.B.Excessive frost on the evaporator.C.Excessive condenser cooling water.D.Insufficient condenser cooling water flow.
单选题Low compressor head pressure in a refrigeration system can be caused by（）.Ainsufficient condenser cooling waterBexcessive condenser cooling waterCair in the refrigeration systemDexcessive refrigerant in the system
单选题The presence of air in the condenser of a refrigeration system will （） the condensing pressure.AincreaseBreduceCmaintain constantDNone of the above is true
单选题If a refrigeration compressor is running continuously without lowering the temperature in the refrigerated space, the trouble may be （）.Aa shortage of compressor oilBwarm food in the refrigeratorCexcessive condenser cooling waterDa shortage of refrigerant
单选题Which of the conditions listed will cause a refrigeration compressor to run constantly without simultaneously decreasing the temperature in the refrigerated space?（）AShortage of refrigerant oilBSlight shortage of refrigerantCExcessive condenser cooling water flowDFaulty expansion valve
单选题An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.Arestriction in refrigerant pipingBair and non-condensable gases in the condenserCwater in the refrigerantDflooding back of liquid refrigerant from the evaporator
单选题Which of the following terms represents the form of heat removed from the refrigerant in the condenser of a refrigeration system?（）ALatent heat of vaporizationBHeat of compressionCSuperheatDAll of the above
单选题In a compression refrigeration plant the refrigerant is under low pressure in the （） and under high pressure in the （）.Acompressor；condenserBcondenser；evaporatorCthrottle valve；evaporatorDevaporator；condenser
单选题If the high-pressure switch on the compressor opens and stops the compressor a possible cause could be:（）Atoo much cooling water going through the condenserBnot enough refrigerant in the systemCa leak in the evaporator coilsDno enough cooling water going through the condenser
单选题When adding oil to a refrigeration system, precautions must be taken to ensure that （）.Athe compressor suction pressure is not too highBall air is purged from the pump and charging fittingsCthe high pressure cutout switch is held open to prevent accidental startingDthe condenser is completely shutdown first
单选题If a refrigeration compressor is short cycling on high head pressure, you should （）.Apurge the condenser if the waterside is dirtyBcheck for proper water flow through the condenserCincrease the high pressure cutout settingDreduce the cooling water flow
单选题While troubleshooting a refrigeration system for low head pressure, liquid refrigerant flooding back from the evaporator is determined to be the causeIt may be necessary to （）.Achange the expansion valve adjustmentBreadjust the water regulating valve to increase the flow of waterCpurge air from the condenserDclean the waterside of the condenser
单选题One cause of high head pressure occurring in a refrigeration system can be （）.Ainsufficient cooling water flow to the condenserBa low refrigerant charge in the systemCthe liquid valve is open too muchDhigh evaporator superheat
单选题The purpose of the refrigeration system low pressure cutout switch is to （）Aprotect the compressor from liquid flood backBprotect the compressor from low discharge pressureCstart and stop the compressor upon system demandDstart the compressor after a drop in the evaporator pressure
单选题Sweating of the refrigeration system compressor crankcase is caused by （）.Atoo much superheatBinsufficient superheatCsuction pressure too lowDexcessive refrigerant returning to the compressor
单选题In a refrigeration system, if the cooling water to the condenser fails, the（）.Abox temperature solenoid valve will closeBexpansion valve will closeCcompressor will shutdownDking valve will open
单选题Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?（）AA shortage of liquid refrigerantBExcessive frost on the evaporatorCExcessive condenser cooling waterDInsufficient condenser cooling water flow
单选题Which will cause the high pressure cutout to stop the compressor in a R-22 system?（）ACondenser leakageBA shortage of liquid refrigerantCExcessive frost on the evaporatorDNot enough condenser cooling water
单选题When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.Aincrease the amount of cooling water to the condenserBdecrease the amount of cooling water to the condenserCadd more refrigerant to the systemDremove some refrigerant from the system
单选题In the refrigeration system, a shortage of refrigerant is indicated by （）.Athe compressor short cycling on high pressure cut out switchBhigh suction pressureChigh head pressureDbubbles in the sight glass
单选题Refrigerant is normally sub-cooled in a refrigeration or air conditioning system condenser to （）.Amaintain adequate coil back pressureBprohibit flashing in the liquid lineCreduce refrigerant volume in the systemDreduce compressor discharge line loading
单选题Which of the listed components is considered to separate the high pressure side of a refrigeration cycle from the low pressure side of the cycle?（）AThe condenser and the expansion valveBThe king valve and the solenoid valveCThe compressor and the expansion valveDThe condenser and the solenoid valve
单选题If a refrigeration compressor is running continuously without lowering temperature as normal in the refrigerator, the trouble may be （）.Aexcessive condenser cooling waterBwarm food in the refrigeratorCa shortage of refrigerantDs shortage of compressor oil