What is the state of the relay contacts when the coil is energized?

When the coil of a relay is energized, it creates a magnetic field that causes the relay contacts to change their state from open to closed. This action allows electrical current to flow through the circuit connected to the relay, thus completing the circuit. The primary function of a relay is to act as a switch, and when the coil is activated, it closes the contacts, allowing the connected load to operate. This mechanism is crucial in HVAC systems, where relays control various components such as compressors, fans, and other electrical devices, ensuring efficient system operation based on demand or sensor signals. Understanding this operation of relay contacts is fundamental in troubleshooting and diagnosing issues within HVAC systems.