A.drop as the boiler warms up
B.rise as the boiler warms up
C.remain unchanged until the boiler is hot enough
D.rise and fall with the steam demand
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A.filled with water
B.purged
C.cleared of air
D.None of the above is true
A.Safety valves
B.Water tubes
C.Steam stop valves
D.Blow down valves
A.water-tube
B.fire-tube
C.exhaust gas
D.None of the above is true
A.water-tube
B.fire-tube
C.exhaust gas
D.none of the above
A.scaled
B.informed
C.leaky
D.deformed
最新試題
If the head pressure of a reciprocating refrigeration compressor is excessive, （）.
When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.
Thermostatic expansion valves can be adjusted for （）.
The major source of chemical contaminants in hydraulic fluid is （）.
If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump （）.
Which of the listed pumps is NOT a positive displacement pump?（）
If the thermal bulb of an expansion valve is incorrectly placed at the center of the coil instead of the end, it will （）.
Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）
The output volume of a positive fixed displacement pump can be changed only by （）.
A salinity indicator is used to determine the （）.