What should a normally closed float switch connected to an auxiliary drain pan control?

A normally closed float switch connected to an auxiliary drain pan is designed to monitor water levels to prevent overflow. When water accumulates in the drain pan, the float rises and opens the switch. This action is crucial because it serves as a safety mechanism to shut down the system to prevent water damage.

By controlling the contactor coil, the float switch effectively stops the operation of the cooling system. This prevents the compressor and associated components from running when the auxiliary drain pan indicates a potential overflow situation. If the contactor coil is de-energized, the compressor will stop running, reducing the chance of water overflow and associated problems.

The other options involve components that are not directly related to the functionality of the float switch in this context. The heater generally operates independently of the drain pan's condition, the compressor's operation depends on the contactor coil being energized, and the blower motor is typically not controlled by the float switch in this type of setup. Thus, the float switch's primary role is to protect the system from excessive water accumulation by controlling the contactor coil.