How to Troubleshoot a Furnace Ignitor That Glows All the Time

A faulty ignitor will prevent a furnace from functioning properly.

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.

Things You'll Need

• 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.

References

• The Family Handyman: Fall Furnace Maintenance Guide
• HVAC-for-Beginners.com: Ignitor Replacement - You Can Do It Yourself And Save