Glossary of Heating, Ventilation and Air Conditioning Terms

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R-22 Refrigerant

R-22 is a single component HCFC refrigerant with low ozone depletion potential. It has long been used in a variety of air-conditioning and refrigeration applications in a variety of markets. Production of R-22 will cease in 2015 per the Montreal Protocol. Also commonly known as Freon.


R-410A Refrigerant
R-410A is classified as an HFC refrigerant and has no undesirable ozone depleting properties because it does not contain any chlorine. The operating pressures of R-410A are approximately 50% to 70% higher than that of R-22. R-410A systems use synthetic polyol ester (POE) oil. Unfortunately, POE oils are hydroscopic, meaning they readily absorb water. This can degrade the oil, causing harm to the entire system. R-410A systems should not be left open to the atmosphere longer than absolutely necessary.
Reciprocating Compressor
A type of compressor used in air conditioners that compresses refrigerant by using a type of "piston" action.
Refrigerant Lines

Set of two copper lines connecting the outdoor unit and the indoor unit.


Return Air

Air drawn into a heating/cooling unit after having been circulated from the cooling/heting unit output supply to a room.


Return Air Box

This is the sheet metal box that mounts directly to the return air grill. This allows the mating of the return duct to the grill.

 


Return Duct

The central heating or cooling system contains a blower that gets its air supply through this duct. The air from a room will move towards the lower pressure of the return duct. The duct also contains the properties of sound attenuation and is insulated.


Reversing Valve

A device in a heat pump that reverses the flow of refrigerant as the system switches from cooling to heating.


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