What is meant by the temperature split (TD) of an air-cooled condenser?
- Leaving air temperature minus entering air temperature
- Discharge line temperature minus liquid line temperature
- Condensing temperature minus liquid line temperature
- Condensing temperature minus entering air temperature
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D. Condensing temperature minus entering air temperature
Condenser split compares the saturated condensing temperature, taken from head pressure, with the air entering the coil. Condensing temperature minus liquid line temperature is subcooling, a different measurement.
Reference: Air-cooled condensers; condenser split
Air has been left in a system after a repair. Where does it collect while the system runs?
- In the condenser and receiver
- In the evaporator outlet
- In the compressor crankcase
- In the suction accumulator
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A. In the condenser and receiver
Air cannot condense at system pressures, so it is carried to the high side and trapped at the top of the condenser and receiver, where it takes up condensing surface and raises head pressure.
Reference: Noncondensable gases; high head pressure
What is the effect of a higher-than-normal head pressure on the compressor?
- Lower amp draw and higher capacity
- Lower amp draw and lower capacity
- Higher amp draw and lower capacity
- Higher amp draw and higher capacity
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C. Higher amp draw and lower capacity
Raising head pressure raises the compression ratio. The motor works harder for each pound pumped, so current goes up, while volumetric efficiency and net refrigeration effect both go down, so capacity falls.
Reference: Condensing pressure; compressor performance