What does the metering device (such as an expansion valve or capillary tube) do to the refrigerant?
Refrigeration · EPA 608 Core. The correct answer, and the reasoning behind it.
The refrigeration cycle, refrigerant states and pressures, gauges and leak detection.
The question
What does the metering device (such as an expansion valve or capillary tube) do to the refrigerant?
- Raises its pressure so it can condense
- Turns vapor into liquid
- Separates oil from the refrigerant
- Lowers its pressure so it can boil in the evaporatorCorrect answer
Why “Lowers its pressure so it can boil in the evaporator” is correct
The metering device restricts flow between the high and low sides. High-pressure liquid passes through it and drops to a low pressure and temperature, so it can boil in the evaporator and absorb heat.
Source: EPA: Test Topics
Why the other answers are wrong
- Raises its pressure so it can condense — Raising pressure is the compressor's job.
- Turns vapor into liquid — Vapor turns to liquid in the condenser.
- Separates oil from the refrigerant — Oil separation is done by an oil separator, not the metering device.
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