What is a Condenser?

Condensers are the outdoor elements of an air conditioning or heat pump system. They are the heat transfer point (where heat escapes to the outside). Condensers are heat exchangers that compress refrigerants into a hot gas and then condense them into a liquid. Major condenser manufacturers are Carrier, Heil, Fedders, Lennox, Rheem, Tempstar, and AireFlow.

Condenser Parts

Both split air conditioner and heat pump condensers are made of the same basic parts. The condenser cabinet contains the condenser coil, a compressor, a fan, and various controls. The condenser coil can be made of copper tubing with aluminum fins or all-aluminum tubing so heat can be rapidly transferred. The coil withstands a pressure of over 400 psi when the weather is very warm. It should be kept as clean as possible to maintain its heat transferring efficiency.

The condenser fan is a vital part and circulates the air across the coil to facilitate heat transfer. If the flow of air is blocked, the efficiency will be impacted or the compressor could fail. The area around the compressor's coil and fan must be free from dirt so that maximum airflow can take place. The compressor is the heart of the system since it compresses the refrigerant and pumps it to a coil in the form of a hot gas. In air conditioners this is cooled at the condenser into a warm liquid, and passes through a pipe into the evaporator coil where it expands and cools. In heat pumps, the hot gas is pumped directly to the evaporator coil to provide heat.

Condensers In Air Conditioning

Condensers used only in air conditioning do not have many controls. A contactor is used to switch the power on and off. Capacitors start and run the motors. Some optional controls like brownout time delay, hard start kit, crankcase heater, and low ambience control are available. The compressor is protected by the brownout time delay, which shuts the contactor off when voltage drops and too much current is pulled in by the motors.

Heat Pump Condensers

These have controls that are more complex than those of the air conditioner. In addition to the contactor, capacitor, and other optional controls, there is also a reversing valve, defrost timer, and an adjustable temperature sensor. The flow of compressed gas is directed by the reversing valve to the condenser coil for air conditioning or to the evaporator coil for heating. The condenser coil extracts heat from air outside the home. When it does this, it becomes very cold and frost collects on it. An excess of frost restricts the flow of air, reducing the coil's effectiveness. The defrost control automatically switches to the air conditioning mode even without the condenser fan running. This makes the ice melt when the hot gas runs through the coil, after which the system switches back to heating mode.