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Discussion Starter · #1 ·
My 5-year old high-efficiency ICP furnace won't stay lit with the burner panel on.
With the panel on, I look through the little window, and the last burner (where the flame sensor is) flickers and then goes out after 30-60 seconds. The fan keeps going and it cycles through that way a few times. The LED code suggests "failure to ignite" (which I can see is not the case) or "flame sense lost", then eventually "soft lockout."
When I take the burner compartment panel off, everything works fine, but I'd rather not leave it like that, with an exposed flame.
Both the air filter and the flame sensor have been replaced recently. The furnace was doing this same thing a month ago, so I replaced those 2 items. I verified that all of the exhaust pipes that I can reach are clear. (We did recently have a large snow, but the last 2 days have been warm enough that a whole lot of that has melted, and the problem didn't start until this morning, 3 days after the big snow.) What ultimately seemed to work last month was opening more ducts/vents wider than I had them previously. It worked fine for a month, then started misbehaving again.
Please help! Thanks
 

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Discussion Starter · #3 ·
The 4th/last burner sputters and goes out. Since thats where a flame sensor is, the others go out a moment later.
 

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Clean out burners/orifices and try again. That flickering burner may not be getting enough gas.

Also when you say the fan keeps running do you mean the ID fan or the forced air blower?
 

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The intake pipe outside may have sucked in snow or the exhaust gas recirculated back into it. Taking the cover off gives it more combustion air. Take a shop vac that can blow air and stick it on the intake pipe outside and turn it on and see if air blows into the furnace. You may have to use a heat gun or hair dryer and blow heat in to defrost it. A leaf blower also works. Same thing can happen to the exhaust but it is less likely as it is warm and pushing out not sucking in like the intake.
 
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