How to Replace a Thermocouple in a Mobile Home

A thermocouple in a mobile home furnace is a copper wire with a connector on one end and a sensor on the other end. The sensor constantly measures the temperature of the furnace as part of its safety function. The thermocouple will automatically shut off the flow of gas if pilot light goes out. When the thermocouple is defective and in need of replacement the pilot light in the furnace will not stay lit or the burners might not ignite even though the pilot light is on. A mobile home furnace thermocouple is inexpensive and extremely easy to replace.

Things You'll Need

• Drill or screwdriver
• Flashlight
• New thermocouple
• Wrench
• Match or BBQ lighter

Instructions

1. Turn the power to the furnace off at circuit breaker. Remove the front panel of the furnace and turn the gas valve to the off position. Depending on the model furnace you may need a screwdriver or drill to remove the screws on the front panel to remove it. Wait a few minutes to allow the furnace pilot light and thermocouple to cool down if the furnace has been running.

2. Locate the thermocouple which is easy to spot if you look for a copper wire next to the pilot light. Use a wrench to unscrew the connector nut that attaches the thermocouple to the gas valve. Use a wrench to unscrew the nut found at the bottom of the pilot burner assembly bracket and remove the old thermocouple.

3. Install the new thermocouple by connecting it to the pilot burner assembly bracket and tightening the nut at the bottom of the bracket using a wrench.

4. Attach the thermocouple end fitting to the gas valve and turn the nut by hand. When the nut feels hand tight, use a wrench to make ¼ turn. Turn the power back on.

5. Turn the gas valve to “Pilot”. Hold down the pilot button and use a match or BBQ lighter to light the pilot. When the pilot lights continue holding the button for at least 30 seconds then slowly release the button. Turn the gas valve to the “On” position. Replace the front panel. Adjust the thermostat to the correct temperature.

Tips & Warnings

• A correctly installed thermocouple should be ½ inch in the pilot light flame.

• To avoid damage do not over tighten the nut to the gas valve.

References

• “The manual for manufactured/mobile home repair and upgrade”; Mark N Bower; 2005
• Furnace Pilot Light
• Furnace parts

Resources

• Mobile Home Furnace Troubleshooting
• Furnace Troubleshooting