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Heating & Air Conditioning

Gas Furnace Issue...

14 years ago

wanted to see if anyone could at least diagnose a problem I have been having with my gas furnace. The hot surface igniter lights up, the therm coupler opens and the gas burners fire, it stays on for about 15-20 seconds and then right as the blower kicks in the valve shuts off and the flames go out. It will cycle like this a few times and then fire normally for a while before it acts up again. I did notice today that when it was acting up that when the igniter lit the burners, a few of the burners weren't lighting and of course it would kick off and cycle again.

Any thoughts?

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Comments (4)

paulbm
14 years ago
if you look at your burners the glow bar that lite the burners is at one end and at the other end there is a thing that looks like a nail right by the burner. That is a flame
rod. When the burner lites it has to go all the way down to the last burner so the flame can hit that flame rod to prove to the control board that we have flame. this has to
happen in a short time or the control board will turn off
on safety. That flame rod has to be cleaned with fine sand paper or it can also turn flame. You might have to take your
burners out and clean them good to see if you can get them to lite off better. Paulbm
dobbsrb
14 years ago
I have a similar issue with my Amana gas pack. The repair folks think it is insufficient fresh air into the conbustion chamber. They are trying to seal the air vent with high temperature stuff.

This has slowed down the problem.
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paulbm
14 years ago
You are right on the burner air. Sometimes it too much and other times it not enough, or the way it is introduced into the burners. But also make sure the burners a real clean and also make sure the gas pressure in set right. Keep in mind that the burner cover has to be off to set gas pressure.
later paulbm
handy-man
14 years ago
Hi Erocki,

I've been doing HVAC for almost 17 years, maybe I can help.

First you need to be specific about the age and brand of your furnace. When you said hot surface ignitor, I am assuming that it's a newer type furnace.

"I did notice today that when it was acting up that when the igniter lit the burners, a few of the burners weren't lighting and of course it would kick off and cycle again. "

- There are two main reasons
1. There are debris/dirt/restriction on manifold (burner's area)
2. Your gas pressure is too low
First get a vacum and clean out all the dirt you can see. If that doesn't solve the problem, then you may want to call a service tech to check the gas pressure.

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