Glossary

A grille over an air supply duct having vanes to distribute the discharging air in a defined pattern or direction.

An air cooler that removes moisture from the air. This unit reduces water vapor in air by cooling the air below the dew point; removing water vapor from the air by chemical means, refrigeration, etc.

A furnace that pulls in return air from the top and discharges warm air at the bottom.

The process of removing ice or frost buildup from the outdoor coil during the heating season.

Direct current electricity. This type of electricity (as opposed to Alternating Current, or AC) flows in one direction only, without reversing polarity.

Found in ductwork, this movable plate opens and closes to control airflow. Dampers can be used to balance airflow in a duct system. They are also used in zoning to regulate airflow to certain rooms.

Canadian Standards Association.

A computation that measures the amount of heating or cooling needed for a building. A degreeday is equal to 65 degrees Fahrenheit minus the mean outdoor temperature.

A switch that can repeatedly cycle, making and breaking an electrical circuit. When ample current flows through the A-coil which is built into the contactor, the resulting magnetic field causes the contacts to be pulled in or closed.

The fan that distributes air over the aircooled condenser.