How to Troubleshoot a Furnace Ignitor That Glows All the Time

The furnace has a hot surface ignitor installed near the burners of the unit. The ignitor has a filament that glows when an electrical current runs through it. The glowing also produces heat. A furnace ignitor that constantly glows will eventually burn out, preventing your furnace from igniting. There are a few troubleshooting steps you can take to try to fix a faulty ignitor, which is pretty easy to replace.

Screwdriver
Compressed air
Emery cloth

Instructions

- 1
  Turn off the electrical supply to the furnace at the circuit breaker.
- 2
  Remove the screws from the front cover of the furnace using a screwdriver.
- 3
  Locate the ignitor on the underside of the burner. Lift the ignitor out from its location.
- 4
  Inspect the ignitor for signs of cracks or burning along the filament. Replace the ignitor if there are cracks or extensive burn marks.
- 5
  Follow the wire coming out the back of the ignitor. Make sure the connectors are completely plugged in.
- 6
  Blow dust and dirt off the ignitor with a can of compressed air. Dirt may prevent the ignitor from reaching maximum heat, causing it to run constantly.
- 7
  Locate the flame sensor next to the ignitor. Rub the end of the sensor with emery cloth to clean it. A faulty sensor may cause the ignitor to continue running.

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