Where can a limit control be wired in a gas-fired furnace?

A limit control serves as a safety device within a gas-fired furnace, ensuring that the system does not overheat by shutting off the burners if the temperature rises beyond a safe threshold. The capability to wire a limit control in both high and low voltage circuits allows for greater flexibility in the electrical design of the furnace.

In the high voltage circuit, limit controls can be integrated to directly manage the operation of the burner or the blower motors. This enables the limit control to cut off power if a hazardous temperature is detected, directly affecting the operation of components that handle higher voltages.

In the low voltage circuit, limit controls are often connected to the thermostat and the control system of the furnace. This integration ensures that safety is maintained without interrupting the full operation of the furnace, allowing it to communicate with other low voltage components like the thermostat.

By allowing for wiring in either circuit, the limit control can effectively monitor and respond to temperature changes in various sections of the heating system, enhancing safety and operational efficiency.