Which terminals energize the fan motor during the heating cycle?

In a heating system, the terminals that energize the fan motor during the heating cycle are crucial for ensuring the proper airflow and distribution of heat. The terminals that represent the control functions of the system typically involve connections indicated by R (the power supply from the transformer), C (common), and the additional terminal designations like SEC1 and SEC2, which are used for specific functions in fan operation.

During the heating cycle, the system needs to engage the fan to circulate warm air throughout the space effectively. When the thermostat calls for heat, it closes the circuit between R (the power source) and W (the heating signal), but the fan operation is also influenced by additional terminals that may connect to the fan relay or control board. By including SEC1 and SEC2, the control circuit is equipped to energize the fan motor since these terminals signify the secondary controls or staging for the fan operation, enabling it to deliver the heated air as intended.

Understanding how these terminals function together is essential for diagnosing and troubleshooting heating systems, ensuring that the fan operates reliably to maintain comfort in a home or building.