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单选题
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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更多 “单选题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 systemB oil entrained in the refrigerantC less than a full charge of refrigerant in the systemD ice crystals forming in the refrigerant” 相关考题
考题
Some refrigeration systems have chemical moisture indicators installed in conjunction with the sight glass in the liquid line If excess moisture is present in the system, the indicator willA.activate the driersB.change colorC.secure the compressorD.add a predetermined amount of liquid drier
考题
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
考题
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.
考题
The flash point of a liquid refers to the temperature ______.A.at which a liquid will give off inflammable（易燃的） vaporsB.at which a liquid will burn steadilyC.at which a liquid will explodeD.that a liquid must reach before it will flow readily
考题
单选题Some refrigeration systems have chemical moisture indicators installed in conjunction with the sight glass in the liquid lineIf excess moisture is present in the system, the indicator will （）A
activate the driersB
change colorC
secure the compressorD
add a predetermined amount of liquid drier
考题
单选题A refrigeration system compressor crankcase is sweating or unusually coldThis is an indication of（）.A
a shortage of refrigerant in the systemB
air in the systemC
an accumulation of liquid refrigerant in the crankcaseD
a shortage of oil in the crankcase
考题
单选题When liquid reaches the compressor of a refrigeration system through the suction line, the condition is called （）.A
flooding backB
superheatingC
overflowingD
recycling
考题
单选题In an operating refrigeration system low on refrigerant, a liquid line sight glass will（）A
be clearB
be blueC
be light greenD
show bubbles
考题
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 （）.A
restriction in refrigerant pipingB
air and non-condensable gases in the condenserC
water in the refrigerantD
flooding back of liquid refrigerant from the evaporator
考题
单选题Refrigerant is normally sub-cooled in a refrigeration or air conditioning system condenser to （）.A
maintain adequate coil back pressureB
prohibit flashing in the liquid lineC
reduce refrigerant volume in the systemD
reduce compressor discharge line loading
考题
单选题Before liquid can flow into a pump, the air in the suction line must be （） sufficiently to cause the liquid to flow into the suction chamber.A
filledB
evacuatedC
compressedD
charged
考题
单选题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 refrigerantB
Excessive frost on the evaporatorC
Excessive condenser cooling waterD
Insufficient condenser cooling water flow
考题
单选题Air entering an air-cooled refrigeration system is indicated by （）.A
frosting of the liquid lineB
higher than normal head pressureC
a clear sight glassD
abnormally cold reefer boxes
考题
单选题In the refrigeration system, a shortage of refrigerant is indicated by （）.A
the compressor short cycling on high pressure cut out switchB
high suction pressureC
high head pressureD
bubbles in the sight glass
考题
单选题A liquid indicator sight glass is useful in determining whether or not a refrigeration system is sufficiently chargedIt is generally located in the（）.A
high pressure liquid lineB
low pressure liquid lineC
high pressure vapor lineD
low pressure vapor line
考题
单选题A liquid sight flow indicator in a refrigeration system is examined and gas bubbles are noted in motion with the fluid flowThis means （）.A
the system is fully chargedB
there is air leaking in from the condenserC
ice crystals are forming in the refrigerantD
the system contains less than a full charge of refrigerant
考题
单选题Which of the following statements is correct concerning a typical shipboard multi-coil refrigeration system?（）A
The liquid receiver functions to collect and remove non-condensable gasesB
A thermostatic expansion valve is used to control refrigerated space temperatureC
Refrigerant temperature in an evaporator is directly related to refrigerant pressureD
Dehydrators must be used continuously in a refrigeration system
考题
单选题The flash point of a liquid refers to the temperature （）A
at which a liquid will give off inflammable vaporsB
at which a liquid will burn steadilyC
at which a liquid will explodeD
that a liquid must reach before it will flow readily
考题
单选题One cause of high head pressure occurring in a refrigeration system can be （）.A
insufficient cooling water flow to the condenserB
a low refrigerant charge in the systemC
the liquid valve is open too muchD
high evaporator superheat
考题
单选题The purpose of the refrigeration system low pressure cutout switch is to （）A
protect the compressor from liquid flood backB
protect the compressor from low discharge pressureC
start and stop the compressor upon system demandD
start the compressor after a drop in the evaporator pressure
考题
单选题The accumulation of air and other non-condensable gases in a refrigeration system will （）.A
cause a loss of the liquid sealB
create a vapor lock in the liquid receiverC
collect in the condenserD
cause foaming of the oil in the crankcase
考题
单选题Which of the listed statements is correct concerning refrigeration systems?（）A
Dehydrators must be used continuously in a refrigeration systemB
A 25 ton refrigeration system has the same cooling effect as melting 25 tons of ice in 24 hoursC
A thermostatic expansion valve is used to control refrigerated space temperatureD
The liquid receiver functions to collect and remove non- condensable gases
考题
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 （）.A
change the expansion valve adjustmentB
readjust the water regulating valve to increase the flow of waterC
purge air from the condenserD
clean the waterside of the condenser
考题
单选题A purge recovery system is used in a centrifugal air conditioning or refrigeration system to （）A
purge lube oil from the liquid refrigerantB
recover water purged from the systemC
separate foul gases from the receiverD
purge non-condensable gases without losing refrigerant
考题
单选题The receiver used in a refrigeration system（）A
stores liquid refrigerantB
collects non-condensable gasesC
allows refrigerant sub-coolingD
prevents compressor surging
考题
单选题A pressure drop in the liquid line of a refrigeration system may cause（）A
the solenoid valve to seizeB
the compressor to huntC
flash gas to form in the liquid lineD
the expansion valve to freeze open
考题
单选题The presence of bubbles in a refrigeration system liquid line may （）.A
promote refrigerant dehydrationB
be absorbed in the receiverC
cause low condensing pressureD
carry moisture and lead to corrosion
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