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
Excessive circulation of the lubricating oil with the refrigerant in a refrigeration system will cause______.
A.carbon deposits on the compressor suction valves
B.the evaporator temperature to increase
C.rapid corrosion of the thermal expansion valve
D.no operating problems
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
Moisture is removed from a refrigeration system byA.bleeding refrigerant from the condenserB.opening a drain petcock on the oil separatorC.condensing the water in the heat exchangerD.using a dehydrator cartridge
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
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
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.
Sludge may be formed in the oil in the crankcase of a reciprocating air conditioning compressor as a result of ______.A.refrigerant bubbles in the lube oilB.refrigerant reducing the lube oil viscosityC.oxidation(氧化) of the lube oil from overheatingD.reducing the floc or cloud point of the oil
单选题The sudden reduction of pressure occurring within the crankcase of a refrigeration compressor during starting causes the （）.Asudden evaporation of wax crystals in the lubricantBsudden evaporation of entrapped air in the lubricantCrelease of refrigerant from the oil/refrigerant mixtureDrelease of dissolved lubricant from the refrigerant
单选题A refrigeration system compressor crankcase is sweating or unusually coldThis is an indication of（）.Aa shortage of refrigerant in the systemBair in the systemCan accumulation of liquid refrigerant in the crankcaseDa shortage of oil in the crankcase
单选题Refrigeration system compressor crankcase sweating is an indication of （）.Ainsufficient lube oil circulating through the systemBexcessive circulation of lube oil through the systemCinsufficient refrigerant in the systemDan overworked compressor
单选题The primary purpose of oil control rings on a diesel piston is to（）Aprovide a reservoir for cylinder lubricationBpump oil into the combustion space for cylinder coolingCprevent excessive lubricating oil consumptionDallow hydraulic oil film formation on the cylinder
单选题An important consideration in selecting a lubricating oil for use in a refrigeration compressor is for the oil to （）Ahave a high viscosity indexBmix readily with refrigerantChave a high freezing pointDhave a low pour point
单选题Excessive oil foaming in the crankcase of a refrigeration compressor can result in （）.Aoverheated compressor bearingsBexcess lube oil viscosityCcarbon deposits on the compressor piston ringsDwax crystals forming in the lubricant
单选题Excessive lubricating oil consumption in a running diesel engine can be caused by （）Aclogged lube oil pipingBexcessive valve-guide clearanceChigh lube oil viscosityDlow lube oil temperature
单选题Moisture is removed from a refrigeration system by（）.Ableeding refrigerant from the condenserBopening a drain petcock on the oil separatorCcondensing the water in the heat exchangerDusing a dehydrator cartridge
单选题If a refrigeration compressor will not start, the reason may be （）.Athe pressure regulating valve is not closingBan excessive lack of refrigerant in the systemCbadly leaking discharge valvesDworn piston rings
单选题Before charging a refrigeration unit, the refrigerant charging lines should be（）Aflushed with clean refrigerant oilBpurged with the refrigerantCwashed with an ammonia and alcohol solutionDgrounded to compressor
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Refrigerant is circulated through a refrigeration system by the （）.AcompressorBcondenserCexpansion valveDevaporator
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Saltwater is typically provided to a refrigeration system to （）.Acool the expansion valveBprevent refrigerant superheatingCcondense the refrigerant gasDprevent motor overheating
单选题Excessive oil foaming in the crankcase of a refrigeration compressor at start up can cause（）.Acompressor damage from improper lubricationBrefrigerant absorption by the lubricantCincreased viscosity in the lubricantDcarbon deposit on the compressor suction valves
单选题A purge recovery system is used in a centrifugal air conditioning or refrigeration system to （）Apurge lube oil from the liquid refrigerantBrecover water purged from the systemCseparate foul gases from the receiverDpurge non-condensable gases without losing refrigerant
单选题Lubricating oil systems for diesel engine journal bearings are usually lubricated by which of the following types of lubricating oil systems?（）ASplashBGravityCPressureDBypass
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