period four
Expansion Devices
notes
Superheat Setting
IToo little superheat:
K Risk of damage to compressor by liquid refrigerant
IToo much superheat:
K Reduction of system efficiency
K Potential of coil frosting
K Risk of compressor damage due to overheating
Figure 48
A typical recommended superheat setting is from 8 to 12°F [4.4 to 6.7°C].
Too little superheat is risky because it presents a danger of allowing refrigerant to leave the evaporator in the liquid state. As mentioned earlier, the compressor is designed to compress vapor, not liquid. Liquid refrigerant can cause damage to the compressor.
Too much superheat dedicates too much of the tube surface to the production of superheat, reducing system efficiency. In extreme cases, it can lead to coil frosting; it may also cause the compressor to overheat, possibly shortening its service life.
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