Furnace Ignitor and Flame Sensor Repair in Big Bear
Free referrals to independent local heating contractors serving Big Bear Lake, Big Bear City, and nearby mountain communities.
If your furnace tries to light, then shuts off or locks out, the hot-surface ignitor or flame sensor is a common cause. Ignitors crack with age and flame sensors get coated. HomeGuide's national estimates are $100 to $250 to replace an ignitor and $80 to $250 for a flame sensor. A heating contractor can test both.
Last reviewed October 19, 2026.
How does furnace ignition work?
On most modern gas and propane furnaces, the sequence is: thermostat calls for heat, the draft inducer starts, the pressure switch proves venting, the hot-surface ignitor glows, the gas valve opens, and the flame sensor confirms the flame within a few seconds. If any step fails, the control board shuts off the gas and tries again, then locks out after several attempts.
What are the signs of a bad ignitor?
- You hear the inducer run, but the burners never light.
- You can see through the sight glass that the ignitor doesn’t glow, or it glows weakly.
- The furnace works some days and not others, which is common as a cracked ignitor gets worse.
What are the signs of a dirty flame sensor?
- Burners light, then shut off after a few seconds.
- The furnace retries several times, then locks out.
- The blink code points to a flame-sense failure.
Why not do it yourself?
Ignitors are fragile and model-specific, and both parts sit inside the burner compartment next to the gas valve. A technician can also check gas pressure, flame quality, and grounding, which cause repeat failures if missed.
When should you call an emergency furnace pro in Big Bear?
Call for urgent help, and leave the house first where noted, if any of these apply:
- You smell gas (a rotten-egg odor): leave right away without flipping switches, then call 911 or your gas utility (Southwest Gas in the Big Bear Valley) from outside.
- A carbon monoxide alarm sounds, or people feel headache, dizziness, or nausea that eases outdoors: get everyone into fresh air and call 911.
- There is no heat and indoor temperatures are dropping toward freezing, especially with infants, older adults, someone with a medical condition, or water pipes at risk.
- The furnace trips the breaker repeatedly, smells like burning wiring, or shows scorch marks.
- You see flames outside the burner area, heavy soot, or a lazy yellow flame instead of a steady blue one.
- A vacant cabin's thermostat or smart sensor reports the house is losing heat during a cold spell.
If you smell gas or a carbon monoxide alarm goes off, leave the building first and call 911 or your gas utility from outside. Don't wait for a contractor.
Where is ignitor & flame sensor repair help available near Big Bear?
Requests are taken from Big Bear Lake and these nearby communities:
What do people ask about furnace repair in Big Bear?
How long does a furnace ignitor last?
It varies with use and ignitor type. Silicon carbide ignitors are more fragile than silicon nitride ones. Short cycling and handling during service shorten their life.
Can a flame sensor just be cleaned?
Often, yes. A technician can clean light buildup. Replacement makes sense if the sensor is damaged or keeps failing.
What do these repairs cost?
HomeGuide's national estimates: ignitor replacement $100 to $250, flame sensor replacement $80 to $250. Travel and after-hours charges can add to the total.
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