If the suction pressure for an operating refrigeration compressor is below normal, the cause may be ______.A.an excess of liquid refrigerantB.the expansion valve overfeedingC.a fouled compressor suction strainerD.the compressor short cycling
If the suction pressure for an operating refrigeration compressor is below normal, the cause may be ______.
A.an excess of liquid refrigerant
B.the expansion valve overfeeding
C.a fouled compressor suction strainer
D.the compressor short cycling
相关考题：
When adding oil to a refrigeration system, precautions must be taken to ensure thatA.the compressor suction pressure is not too highB.all air is purged from the pump and charging fittingsC.the high pressure cutout switch is held open to prevent accidental startingD.the condenser is completely shutdown first
Excessive oil foaming in the crankcase of a refrigeration compressor is most likely to occur when the compressorA.has run continuously for a long periodB.suction pressure is below normalC.oil level is below normalD.starts after a long idle period
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
If the suction pressure at the refrigeration compressor is below normal, the cause can beA.refrigerant overchargeB.overfeeding by the expansion valveC.a restricted suction strainerD.due to short cycling of the compress
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
The sensing line for the low pressure cutout switch to a refrigeration system is located ______.A.in the chill box(冰箱)B.before the receiverC.on the suction side of the compressorD.on the discharge side of the compressor
An increase in the heat load to a refrigeration system will cause ______.A.the suction pressure to decreaseB.the suction temperature to increaseC.increased ice formation on the evaporator coilD.excessive short cycling of the compressor
Excessive circulation of the lubricating oil with the refrigerant in a refrigeration system will cause______.A.carbon deposits on the compressor suction valvesB.the evaporator temperature to increaseC.rapid corrosion of the thermal expansion valveD.no operating problems
单选题When liquid reaches the compressor of a refrigeration system through the suction line, the condition is called （）.Aflooding backBsuperheatingCoverflowingDrecycling
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Which of the listed operations will cause an automatically controlled refrigeration compressor to restart?（）AClosing of the solenoid valveBClosing of the expansion valveCAn increase in the suction pressureDDecreasing the suction pressure
单选题Insufficient refrigerant in a refrigeration plant may result in （）.Ahigh discharge pressureBfrosting of the crankcaseChigh temperature of the overboard waterDlow suction pressure of compressor
单选题The only means of removing the latent heat of condensation from a refrigerant in the normal refrigeration cycle is by （）.Apassing it through the expansion valveBcondensing refrigerant in the system condenserCpassing the gaseous refrigerant through the heat interchanger on the suction side of the compressorDmaintaining a high pressure on the systems receiver
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If the head pressure of a reciprocating refrigeration compressor is excessive, （）.Athe relief valve should open before the high pressure cutoutBthe relief valve should open and allow the excess refrigerant to flow to the receiverCthe high pressure cutout switch should operate before the relief valve opensDyou should close in on the suction valve
单选题Foaming of the oil in a refrigeration compressor crankcase is caused by （）.Arefrigerant boiling out of solution from the lube oilBliquid refrigerant flooding the compressor and systemClube oil viscosity being reduced by refrigerant dilutionDcompressor suction pressure suddenly increasing
单选题If the suction pressure at the refrigeration compressor is below normal, the cause can be（）.Arefrigerant overchargeBoverfeeding by the expansion valveCa restricted suction strainerDdue to short cycling of the compressor
单选题An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.Aoil foaming in the compressorBhigher than normal suction and discharge pressures with a higher box temperatureChigher than normal discharge pressure with a normal box temperatureDthe compressor to run continuously
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An increase in the heat load to a refrigeration system will cause （）.Athe suction pressure to decreaseBthe suction temperature to increaseCincreased ice formation on the evaporator coilDexcessive short cycling of the compressor
单选题Under normal conditions, the refrigerant enters the compressor in an operating refrigeration system as a （）.AliquidBdry saturated gasCwet saturated gasDsuperheated vapor
单选题The sensing line for the low pressure cutout switch to a refrigeration system is located （）.Ain the chill boxBbefore the receiverCon the suction side of the compressorDon the discharge side of the compressor
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The purpose of the low pressure cut-out switch is to （）.Amaintain liquid refrigerant at the suction of the compressorBmaintain a preset suction pressure to the compressorCstart and stop the compressor at preset operating pressuresDoperate at minimum efficiency
单选题Excessive oil foaming in the crankcase of a refrigeration compressor is most likely to occur（） when the compressor.Ahas continuously for a long periodBsuction pressure is below normalCoil level is below normalDstarts after a long idle period
单选题When a refrigeration compressor motor fails to start, the FIRST thing that should be checked for is a （）.Aloose expansion valve control bulbBlow differential setting on the H-PcutoutCblown fuse in the motor circuitDfaulty suction pressure regulator
单选题Excessive circulation of the lubricating oil with the refrigerant in a refrigeration system will cause （）.Acarbon deposits on the compressor suction valvesBthe evaporator temperature to increaseCrapid corrosion of the thermal expansion valveDno operating problems