How to Replace a Forced Air Heater Thermal Coupler

A forced air heater, as the name implies, uses a blower motor to direct warm air into a room. If the forced air heater uses a thermal coupler, it means the appliance is gas powered. A thermal coupler is a heat switch that opens the gas valve when the pilot light adjusts to the ignition position. When idle, the pilot light burns at a low level. When the heater control is switched on, the pilot flame extends across the thermal coupler. If the part malfunctions, the heater will not light. Replacing a thermal coupler takes less than an hour.

Screwdriver set

Instructions

- 1
  Shut off the heater at the control knob on the appliance, then turn the knob in the gas line connected to the heater clockwise until tight.
- 2
  Open the access cover on the heater, using a screwdriver to remove the screws holding the cover in place. The thermal coupler is between the pilot light tube and the valve for the gas. The coupler has a wire on each end with a bulb in the center. The bulb is typically made of copper.
- 3
  Loosen the screw holding the wire on each end of the thermal coupler. Take out the defective part.
- 4
  Slip the hooks on the end of the new thermal coupler wires around the threaded screws. Tighten the screws.
- 5
  Close the access cover on the appliance and secure it with screws.
- 6
  Unscrew the knob in the fuel line connected to the heater, which can now be ignited normally.

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