how does a contactor work

An HVAC contactor plays a crucial role in the operation of a condensing unit, which is a part of the HVAC system responsible for cooling or heating a space. The contactor is an electrical relay that controls the flow of electrical power to the compressor, condenser fan motor, and other components within the condensing unit.

When the thermostat signals a need for cooling or heating, the contactor receives an electrical signal from the HVAC system's control board or thermostat. The contactor then engages and allows electrical current to flow from the main power source to the compressor and condenser fan motor.

The primary function of the contactor is to facilitate the switching of high-voltage power supply to the appropriate components. It acts as a bridge between the low-voltage control circuit and the high-voltage components. When the contactor is energized, it closes the contacts, allowing the electrical current to flow through the system. This allows the compressor to start running, generating the cooling or heating effect, and the condenser fan motor to circulate air across the condenser coil for heat dissipation.

Once the desired temperature is reached or the thermostat signals a shutdown, the control signal to the contactor is interrupted, and it opens the contacts, cutting off the power supply to the compressor and condenser fan motor. This process helps in controlling the operation of the condensing unit and maintaining the desired temperature in the space.

Overall, the HVAC contactor is an essential component that enables the electrical control of the condensing unit, allowing for efficient operation and temperature regulation within the HVAC system.