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-   -   Furnace only works with door off (http://www.diychatroom.com/f17/furnace-only-works-door-off-58564/)

CWinGA 12-05-2009 01:49 PM

Furnace only works with door off
 
I have a Governaire standard efficiency furnace. The furnace has been cycling every three minutes or so. I noticed that the furnace runs fine with the burner access door off. If i slowly start to put it back on, I can feel a lot of suction and I can see the flame blow out. It seems like the sensors and switches work okay and the furnace is shutting down (correctly) because the flame sensor cannot detect a flame.

Any ideas about what the problem is and how to fix it? Any help is greatly appreciated.

BERVIN 306 - I think you are on the right track. There is no intake pipe. The furnace is in a crawlspace and there is plenty of ventilation, but I think there may be a restriction in the flue causing a pressure drop. I think the inducer fan can produce enough static pressure to overcome the restriction, but not with extra restriction of the access door.

mercdady 12-05-2009 02:28 PM

Without looking at it I can't be positive, but anyway you look at it you probably need a professional. If the flame is being Blown out by the blower coming on you might have a cracked heat exchange. This is very dangerous. Meaning turn it off until it's repaired. Another possibility could be a partially clogged flue. First thing I would do is check your filter. Next I would call a Pro.

Marty S. 12-05-2009 04:23 PM

Sounds like a crack has turned into a massive hole. Shut it off and call a pro.

bervin306 12-05-2009 05:36 PM

Your fresh air intake pipe is most likly clogged. You need air to make fire. That's why it works with the door off. Check your intake pipe there should be a screen right before it goes into the burner box, see if you see any leaves. Also check the outside make sure it is clear. if all else fails blow out the pipe.


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