pressure switch
pressure switch
相关考题：
Situations calling for a matrix organization include outside pressure for dual focus, _____ and pressure for high information processing capability.A . Pressure for clear accountabilityB . Pressure for reduced duplication of effortC . Pressure for shared resourcesD . Pressure for formalized communication
If the head pressure of a reciprocating refrigeration compressor is excessiveA.the relief valve should open before the high pressure cutoutB.the relief valve should open and allow the excess refrigerant to flow to the receiverC.the high pressure cutout switch should operate before the relief valve opensD.you should close the discharging valve
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
Before performing any maintenance on a hydraulic system storing energy in an accumulator, you shouldA.pressurize the system to test for leaksB.bleed off all pressure within the systemC.operate the machine until it reaches normal temperatureD.disconnect the pump pressure control switch
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.
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
The refrigeration system low pressure cutout switch is actuated by______.A.an electric system managerB.a sensing bulb at the tail coil of the evaporatorC.pressure changes in the suction lineD.failure of the king solenoid valve
单选题In a direct expansion type multi-box refrigeration system, the compressor is set up to cycle on and off by the（）ApressurestatBhigh pressure cutoutCsolenoid valveDlow pressure cutout switch
单选题The device used for low-pressure control and high-pressure cutout on a compressor is called a（）AcutoutBpressure controllerCcontroller switchDcutout switch
单选题Refrigerant enters the condenser as a （）.Ahigh pressure liquidBlow pressure vaporChigh pressure vaporDlow pressure liquid
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 were short cycling on the low pressure cutout switch, the probable cause for this might be the （）.Asystem was overcharged with refrigerantBhigh pressure switch was improperly adjustedCexpansion valve strainers were fouledDsuction valves were leaking slightly
单选题If the compressor runs continually, the cause might be the（）Ahigh-pressure cutout switch is jammed openBlow-pressure switch is jammed shutCthermal bulb is not operating properlyDscale trap is clogged
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If the discharge valves on a refrigeration compressor are leaking badly, the compressor should （）.Arun continuouslyBnot startChave high discharge pressureDshort cycle on the high pressure switch
单选题The refrigeration compressor in a water cooled refrigeration system is short cycling on the high pressure cutout switch， One reason for this could be the （）.Asystem is low on refrigerantBhigh pressure cutout switch is improperly adjustedCdischarge valves are leaking slightlyDdischarge valves are leaking excessively
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If the head pressure is too high,（）Athe relief valve should open before the high-pressure cutoutBthe relief valve should open and let excess refrigerant go to receiverCthe high-pressure cutout switch should operate before the relief valve opensDclose in on the suction valve
单选题The compressor in an air-cooled condensing refrigeration system is short cycling on the high pressure cutout switch（）Asystem is overcharged with refrigerantBsystem is low on refrigerantCdischarge valves are leaking excessivelyDdischarge valves are leaking slightly
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If a compressor runs continuously, the cause might be a（）Adefective thermal bulbBclogged scale trapCstuck high-pressure switchDstuck low-pressure switch
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Why does the speaker ask us to consider “turning off a light switch”?ATo show that the climate system is sensitive to light.BTo illustrate the sudden move from one climate state to another.CTo demonstrate how to operate the light switch.DTo explain how the operating mode works under increasing pressure.
单选题Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）AThermal expansion valve frozen openBSuction gas heat exchanger bypassedCCondenser clogged or fouledDHigh pressure cutout switch inoperative