Category: Glossary

Any device that responds to a change in the conditions being measured, permitting the condition to be controlled.

That heat which, when added to or taken away from a substance, causes a change in temperature.

Polyvinyl chloride; a type of plastic. In recent years, PVC has been replacing traditional building materials such as wood, concrete and clay in many areas.

Pounds per square inch gauge.

A chemical substance that produces a refrigerating effect while expanding and vaporizing.

The required amount of refrigerant in a system.

A compressor that uses pistons driven by a crankshaft to deliver gases at high pressure.

A heating and cooling system contained in one outdoor cabinet. This package unit is typically installed on the roof, beside, or sometimes in the attic of a home.

Original equipment manufacturer.

Pounds per square inch.