Abbreviation for equipment capable of operating on alternating or direct current.
Glossary of Terms
Abbreviation for alternating current, a type of electric current in which the polarity is constantly reversing causing the electron flow to reverse.
Air Conditioning Contractors of America.
A heat exchanger consisting of two diagonal coils that are joined together in a manner that looks like the letter "A".
Of or pertaining to sound.
Annual Fuel Utilization Efficiency. A measure of a gas furnace's efficiency in converting fuel to energy. The higher the rating, the more efficient the unit.
Abbreviation for American Gas Association, Inc.
Any device that removes undesirable particles from moving air.
Any device that can change the temperature, humidity or general quality of the air.
The amount of air the system circulates through your home, expressed in cubic feet per minute (cfm). Proper airflow depends on the outdoor unit, the indoor unit, the ductwork and even whether the filters are clean.
An air moving and/or mixing unit. Residential air handlers include a blower, a coil, an expansion device, a heater rack and a filter. Heaters for air handlers are sold as accessories. In some models heaters are factory installed.
Air Conditioning & Refrigeration Institute.
American Society of Heating, Refrigeration and Air Conditioning Engineers.
British thermal unit. The amount of heat required to raise or lower the temperature of one pound of water one degree Fahrenheit. The heat extracted from your home by an air conditioner is measured in BTUs.
British thermal units per hour. 12,000 BTUh equals one ton of cooling.
A burner that obtains all air for combustion from outside the heated space.
The opening through which gas flows to the air/gas mixing chamber of the burner.
A device that uses fuel to support combustion.
The output or producing ability of cooling or heating systems. Cooling and heating capacities are referred to in British thermal units (BTUs) per hour.
The metric temperature scale in which water freezes at zero degrees and boils at 100 degrees, designated by the symbol "C". To convert to Fahrenheit, multiply a Celsius temperature by 9, divide by 5 and add 32 (25 x 9 equals 225, divided by 5 equals 45, plus 32 equals 77 degrees Fahrenheit).
Abbreviation for cubic feet per minute, a standard measurement of airflow. A typical system requires 400 cfm per ton of air conditioning.
Adding refrigerant to a system. This is refrigerant contained in a sealed system or in the sensing bulb to a thermostatic expansion valve.
This is the heart of an air conditioning or heat pump system. It is part of the outdoor unit and pumps refrigerant to meet the cooling requirements of the system.
Vapor that liquefies due to the lowering of its temperature to the saturation point.
In an air conditioner, the coil dissipates heat from the refrigerant, changing the refrigerant from vapor to liquid. In a heat pump system, the coil absorbs heat from the outdoors.
The fan that circulates air over the air cooled condenser.
A switch that can repeatedly cycle, making and breaking an electrical circuit. When sufficient current flows through the coil built into the contactor, the resulting magnetic field causes the contacts to be pulled in or closed.
This is the electric resistance heater installed on compressor crankcases to boil off liquid refrigerant that may have combined with compressor oil. Many newer cooling systems do not require crankcase heaters, however heat pumps do require crankcase heaters.
Canadian Standards Association.
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.