# Furnance burner won't stay on.



## rbogosh (Sep 20, 2007)

2007ken said:


> I have a Goodman furnance about 10 years old, and went to turn on as usual setting the theromstat to heat.
> The furnance comes on and burners ignite and then quickly go out.
> The fan blower stays on. I turn off, waited and then tried again...
> same result. Model is GMP075-3. Never had a problem before..furnance
> burner flame goes out quickly.


You seem to have a problem that require a teck I would make sure that your filters, blower fan cage
are clean and the burner section as well. the pilot flame sensor may needed to be replaced not giving a strong constant signal to your circuit board . Some cicuit boards have a trouble light on them and blinks to tell you what did not work


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## rbogosh (Sep 20, 2007)

I have the same furnace and the same problem I found that if you make sure that the sheet metal pieces in front of the burner section is in correctaly AND YOUR HEAT EXCHANGER is not cracked. The fire will keep the pilot sensor in play. keeping a strong constant signal to the elcetronic control board. which keeps the unit running. Another thought get a better furnance I was a HVAC Teck for 40yrs and had alot of trouble with early Goodman units..


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## jogr (Jul 24, 2007)

I had the same issue a few years ago. I cleaned the flame sensor by lightly rubbing with emory cloth. That worked for a while but I think I ended up replacing the sensor after it did it a second time. No problems since then.


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## marsovbrilan (Sep 24, 2007)

*GMP100-4 help*

My parents have a gmp100-4 rev b unit and it's not blowing hot air. They smelled what they think is gas and called the city to handle the situation thinking it's a gas leak. The city guys explained that it was the igniter in the unit that was bad. Is this true? Are there things I can do or check to verify? If they do need a new igniter can, where can I get it for cheap? My parents dont speak much english and I hate to see them get taken advantage of. Any help will do.


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## rbogosh (Sep 20, 2007)

*Gas furnace not igniting*

Ther are so many senerios on why the the unit will not ignite, spark is supplied from an ignitor that supplies the spark to the pilot. But unless you do not have the savy to test the unit you have the option of changing out the ignitor, Honeywell has a fits all unit and you can get it from your local w.w. Graingers store ($125.00) with some wiring alterations or go to a Goodman dealer and get the drop in. But it seems to me that you SHOULD GET real help. You Parents lives are more important


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## marsovbrilan (Sep 24, 2007)

i think the igniter comes on and then goes off. Right now they are not running the unit. If i get them to turn it on and tell me exactly what is happening when they turn it on , can you tell me what to be looking for ? On the access pannel i see some troubleshooting code explaining what the number of blinks mean and i also see 3 red led's on a circuit board. I'm assuming that the blink code descriptions refer to one of these led's so my questions is which one and what would be the procedure to accurately observe this action? should they turn the unit on heat and look at the igniter mechanism? The second pannel which leads to the led's i'm talking about is beneath the first panel and a switch that becomes depressed turns the unit off when the second panel is removed. I'm trying to gather as much info as possible before i call someone or actually do anything.


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## rbogosh (Sep 20, 2007)

If the front panel is off the unit will not fire as there is a switch on panel stops the unit from working also the geen flashing lights DO indicate as to what is not working I do not have the info as to what blinks are if you have a manual you may find out and also look on the wiring diagram on the unit it also may give you the info.. Does this furnance have an addtional fan on the exhaust flue? (other than the one on the furnace itself) because if the proving swithch on is not making the furnance wont fire as well and if you fire the unit do you hear clicking if so the ignitor is working and check the high voltage wiring from the ignitor to the pilot assy make sure all connections are connected other than this I DUNNO


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## Buckeyetech (May 4, 2007)

The flame sensor is probably dirty. Clean it with Scotchbrite (cleaning with emory cloth leaves a rough surface allowing for buildup and they hardly ever need replaced unless they are so rusted, pitted or scatched that they won't clean up or the porcelan (sp?) is cracked.


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## KenG_Sacto (Mar 2, 2008)

*Goodman Unit similar issue, Fan Ran uncontroled- then gas shut down 3-5 sec*

I also have a Goodman GMP unit, about 12 years old with same issue. The unit had been operating intermittently. Fan would run continuously or just out of the blue- even with both thermostats in OFF. Cleaned unit checked all sensors
1) Rollout sensors = Good
2) Flame Sensor = Good
3) Limit Switch = Good
I also cleaned the control board B18099 -06 (dust-reset connectors) Problem still existed. However I now had issue with gas shutting down after 3-5 seconds. I read someone else’s post about them placing a pop cycle stick between relays and this fixed their problem (by making improved contact of bad solder joint). I used the plastic end of screwdriver and placed some pressure onto the control board while unit was cycling. With no pressure gas shut down, on 2nd attempt of pressure on the board the gas stayed on! I shutdown the power, dismounted control board from 4 stand-offs and used a 30w solder iron to reflow all the solder joints on the control board.

Fired up the unit.... All works! So issue was most likely cold solder joint from 12 years of vibration and temp in my attic. I’m glad there is a forum like this for DIY’s to share ide


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## baseball27 (Feb 26, 2008)

Probably the flame sensor, take a wire brush or a fine sandpaper to the metal rod and make sure its not the ignitor. If you do that it should work, but if you have a circuit board make sure you have 110 volts coming out of the board for the ignitor to light


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## angusii (Mar 4, 2008)

Yes we need to know what the lights are flashing. The cover plate usually has the diagnostic codes on them. Tells us what it says and maybe we can help more.


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