What is the function of a relay in an HVAC system?

The function of a relay in an HVAC system is primarily to switch electrical circuits on and off. A relay is an electrically operated switch that uses an electromagnet to mechanically operate a switch. When an HVAC system requires a component, like the compressor or fan motor, to be turned on or off, the relay is activated, allowing the control circuit to manage larger loads without directly handling high-voltage electricity.

In HVAC systems, relays are commonly used to control components such as compressors, fans, and pumps. This allows for safer operation, as the low-voltage control circuit can operate larger loads without directly interacting with them. This also facilitates automation and control strategies in modern HVAC systems, improving efficiency and reliability.

The option that indicates backup heating, a timer for fan operation, or controlling refrigerant flow relates to different functions performed by specific components in the system and does not convey the primary role of the relay itself.