Burner ignites then shuts off


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Old 01-07-10, 07:43 PM
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Burner ignites then shuts off

This is an 8 y/o Frigidaire gas heating unit.


When I turn the heat on, the electronic ignition comes on, the gas turns on, it ignites and the blower comes on and everything seems to be working normally. Then, after it goes through several cycles of working normally, the electronic ignition comes on and ignites the gas then everything but the blower immediately shuts off. It starts going through this process of igniting and instantly shutting off over and over. I found that I can turn the unit off for a few seconds, then turn it back on, and it will run normally for a time, but eventually it starts this shutting off/on cycle.

Any idea what the problem is? Supposed to be 14 degree here tomorrow.
 
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Old 01-07-10, 10:15 PM
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I'm supposing you have a hot surface ignition system, with an ignitor that glows white hot to light the gas.


If so, a common cause of the symptom you describe is a flame sensor that has become coated with invisible oxides that needs to be cleaned.

The flame sensor is typically on the opposite side of the furnace from the ignitor, and is a round rod that sticks up into the flames. It has a single wire coming out the bottom that goes over to the ignition module.

If that's what you have, remove the flame sensor and clean it with a wire brush or some fine sandpaper. You don't need to cut into the metal, you are just cleaning those oxides off the surface.

Try that and see what happens.
 
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Old 01-08-10, 07:42 AM
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I do have that hot surface ignition system and there is a sensor on the right. I removed and wire brushed it (it was about 3 1/2 inches long with a porcelain base and 1 wire connector).

One more thing though, and I didn't know this before I removed the cover and watched But, when I ran the system, after I cleaned the sensor, I noticed that when I turned the heater on, everything seemed to work normally for about 5-10 minutes, but sometimes less, (meaning, the ignition comes on, ignites the flames and the blower starts etc..) but it shuts down before it warms enough for the thermostat to shut it off. When it shuts down, the red fault condition light blinks continuously (I counted something like 17 blinks or so - I guess 17 blinks would be continuous). Then, the system starts up again, the ignition lights the gas, the blower comes on and blows etc..then it shuts down after some time and the red light blinks...It does this over and over. I assume that if I waited long enough, it would start shutting off like I described before.

Hope that made sense...
 
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Old 01-08-10, 08:35 AM
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Often the diagnostic codes are listed on the fan compartment cover of the furnace, the manual of the furnace, the ignition control module itself or some other location. See if you can find what the code represents.
 
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Old 01-08-10, 09:01 AM
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My diagram says when the red light blinks continuously that that indicates "false flame or gas valve relay shorted".


Edited to add: since I cleaned the sensor, the system doesn't shut down instantly like it was before (so far) maybe cleaning the sensor cured that but it is still shutting down, with the red light blinking continuous, then starting back up running for some time, then shutting down over and over. ...it just stays lit for a while rather than instantly shutting down now.
 

Last edited by Fade; 01-08-10 at 09:36 AM.
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Old 01-08-10, 09:35 AM
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2006 Ducane Gas Furnace

Hello: I have a 2006 Ducane gas Furnace same problem the igniter will light the gas run for 20sec's then go out it will do this 2 more times then will not come on at all?.

Is this the the flame sensor as well ?

Regards


D
 
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Old 01-08-10, 10:02 AM
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Originally Posted by Denny B View Post
Hello: I have a 2006 Ducane gas Furnace same problem the igniter will light the gas run for 20sec's then go out it will do this 2 more times then will not come on at all?.

Is this the the flame sensor as well ?

Regards


D


Unfortunately, it rapidly becomes confusing to try to deal with two or more problems on the same thread.

Please repost on a new thread.


No harm in cleaning the flame sensor --- it should be done annually anyway. And it might help.
 
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Old 12-29-12, 09:17 PM
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SeattlePioneer... So I just got home from Seattle tonight to NJ. My furnace did the classic start up, flame out, but the blower keeps going. You solution solved my problem in 5 minutes. (Search time included!) Thanks for posting!!! Kind of ironic that a guy from Seattle helped me solve my problem and save $$ on getting a repairman out.

Thanks you!!!
 
 

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