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That stubborn furnace flame sensor is finally clean and working! | HVAC Technicians - Hub Chatter

That stubborn furnace flame sensor is finally clean and working!

I had this one customer with an intermittent furnace shutdown. Every time I checked, it seemed fine, but it would fail again in a week. Today, I took extra time to really scrub the flame sensor with fine sandpaper, not just a quick wipe. I also checked all the connections and made sure the grounding was solid. The furnace has been running smoothly for three days now, and the customer is thrilled. It feels great to solve a problem that's been bugging me for a while. Just wanted to share this little victory with folks who get it!

3 comments

3 Comments

danielm486mo ago

Units run for years with a barely touched sensor" is a bit of a stretch. Sure, they can, but in my experience a dirty sensor is the most common cause for that exact lockout code. It's not overthinking, it's just the basic fix. Like how @emery549 holding the button longer wasn't magic, it was probably letting the thermocouple heat up enough. A good clean and checking the ground isn't a random guess, it's the standard first step for a reason. Skipping that just means the callback next week.

riley_sullivan6mo ago

Ugh, do we really need to make a whole thing about a flame sensor? Sometimes these fixes just hold for no clear reason, and you spent all that time on it. I've seen units run for years with a barely touched sensor, so maybe it was just its time to work. Honestly feels like we overthink the small stuff when the problem might have fixed itself. Not every little victory needs a deep explanation.

emery5496mo ago

Man, your whole comment just reminded me of my old water heater pilot light. Spent two hours trying to relight it perfectly, following the manual to the letter. Gave up and just held the button down longer on a whim, and it finally caught. Maybe it was the extra time, maybe it was just a draft. Fussing over it definitely didn't help. Sometimes you just stop messing with it and then it works. Who even knows how much gas I wasted before that.