单项选择题X 纠错
A.high-pressure cutout switch is jammed open
B.low-pressure switch is jammed shut
C.thermal bulb is not operating properly
D.scale trap is clogged
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单项选择题
A.in the middle of evaporator coils
B.near the evaporator coil outlet
C.near the evaporator coil inlet
D.on the bottom row of evaporator coils
单项选择题
A.amount of superheat in the vapor leaving the coil
B.amount of superheat in the liquid
C.temperature in the evaporator coils
D.pressure in the evaporator coils
单项选择题
A.stop the refrigerant from flowing
B.force the refrigerant to flow
C.cause the refrigerant pressure to rise
D.cause the refrigerant pressure to fall
单项选择题
A.the expansion valve will move toward the wide open position
B.the expansion valve will move toward the closing position
C.the feeler bulb will conveys the high temperature
D.the superheat degree will raise
单项选择题
A.move in an opening direction
B.move in a closing direction
C.either open or close
D.not move at all
单项选择题
A.help preheat the air for the furnaces
B.help preheat the feedwater
C.protect economizer from excessive heat
D.prevent excessive furnace heat losses
单项选择题
A.the bilges
B.the periscope
C.the water level
D.the oil pressure
单项选择题
A.excess stresses will not be set up in the boiler
B.the decks will not be covered with soot
C.the soot will be swept toward the uptakes
D.there will not be a loss of steam pressure
单项选择题
A.bottom-blow valve
B.skin valve
C.feed-check valve
D.feed-stop valve
单项选择题
A.a system with a Hydraulic Power Supply (HPS) unit
B.a system with roller guides for exhaust valves
C.a system with an electronically controlled Alpha Lubricator
D.a system directly powered by electric motor