Comparison Guide
Ignitor vs Flame Sensor: Which Part Failed?
Ignitor and flame sensor faults look similar at first, because both stop heat. The pattern tells them apart. An ignitor fault usually means clicking with no flame at all. A flame s
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Licensed and insured style service · Mon-Fri: 7AM - 7PM, Sat: 8AM - 4PM, 24/7 Emergency · Serving Hendersonville and Sumner County, TN
Ignitor and flame sensor faults look similar at first, because both stop heat. The pattern tells them apart. An ignitor fault usually means clicking with no flame at all. A flame sensor fault usually means burners light, run for a few minutes, then shut off.
The ignitor glows to light the gas. When it cracks, gas never gets a spark, so the furnace shuts down for safety. The flame sensor proves a flame is present. When soot coats it, the board loses that signal and shuts the furnace down, even though the burners lit fine.
Testing confirms which part failed, because both patterns can also point to gas, control, or airflow faults. We test ignitor, flame signal, and gas in order, then replace only the failed part. If both parts are worn, we explain that too, and we give you a price before work starts.
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Frequently Asked Questions
How do I tell ignitor from flame sensor?
Clicking with no flame points to ignitor. Lighting then shutting off after minutes points to flame sensor.
Can both fail at once?
Yes, especially on older furnaces where both parts have aged together.
Can cleaning fix either?
Cleaning can fix a sooty flame sensor. An ignitor that is cracked needs replacement.
Should I replace both to be safe?
Only if both have failed or are clearly worn. We test first and replace only what has failed.
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No Heat? Do Not Wait It Out
Licensed and insured style service. Mon-Fri: 7AM - 7PM, Sat: 8AM - 4PM, 24/7 Emergency. Serving Hendersonville and Sumner County, TN.