Goodman Furnace Burner issue

hansim4 · 10-07-2009, 02:52 PM

Hello. I have a Goodman GMP100 furnace that is having some issue with burner flame. When the flames come out from the 4 tubes, the flames from 2 left tubes go out immediately and only the right 2 tubes have flames. This last for about 2 to 3 seconds and then flames from all tubes goes out completely and whole cycle starts all over again. Sometimes, the flames from the last 2 tubes goes out and then come back immediately and stays lit. In this case, the system works properly. The problem is that chance of this happening is only about 50% time.

Does anyone know why the flames from the left 2 tubes may go out? Do I need to clean these tubes periodically? Can it be flame sensor rod? If it is, then how can right 2 tubes have flames on?

Any help would be highly appreciated.

Thanks in advance.

SKIP4661 · 10-07-2009, 05:04 PM

Based on the furnace reputation and experience, you probably have heat exchanger issues. Should have it checked.

hansim4 · 10-07-2009, 05:10 PM

I put new exchanger earlier this year so I would be surprised that's the cause. Also, I don't see flames blowing back as it used when I had the heat exchanger issue..

yuri · 10-07-2009, 06:33 PM

The gas valve may be overfiring (pressure too high) and the flames are lifting away from the burners. That is a DANGEROUS situation at any time as raw gas is shooting into the chamber and can re-ignite (BOOM). Get a tech to check the manifold pressure etc.

hansim4 · 10-08-2009, 11:24 AM

If I want to reduce the gas pressure, which way do I turn the valve? I am assuming I have to turn it counter clockwise to do this but just want to check before I do this.

yuri · 10-08-2009, 08:26 PM

That may not be the problem. The valve itself may have a faulty regulator and won't maintain a correct pressure. DO NOT touch the gas valve regulator as it is VERY VERY sensitive and you need a manometer to monitor the gas pressure while doing so. Too low a pressure will cause delayed ignition and more danger. You need an experienced tech or risk your families safety.