Goodman/Janitrol GPD100-4 Burners not firing consistently

DaveK · Mon Mar 02, 2009 2:30 pm

I have a Goodman/Janitrol GPD100-4. After the heating element gets hot and the gas ignites, I get inconsistent firing across the four burners. The one on the far right with the heating element burns correctly, but the other three ignite and turn off repeatedly. This lasts for about 4-5 seconds and then the gas cuts off. This cycle will repeat for the duration of the cycle and the temperature of the house may or may not rise until the furnace cuts off. I usually have to turn the thermostat down at least one degree below the current temp and then back up at least one degree over the current temp to get it to kick on again. In addition, the strange thing is that I have witnessed all four burners burning properly for 10-15 seconds on many occasions, so the problem seems intermittent, although the on again/off again is the most common symptom. Any help would be great. Thanks!

Robert · Wed Mar 04, 2009 2:15 am

Hi,

Check burners and burner orifices for blockages of any kind (spider/web is common).

IF all ok, best to call an hvac tech in to properly diagnose problem for safety.

Thanks,
Robert

DaveK · Wed Mar 04, 2009 9:24 am

Thanks for your response, Robert! I took it all apart, cleaned everything including a light sanding of the flame sensor, and put it all back together. When I fired it up I got the same result, at first. After about 30 minutes of normal operation, all four burners were blazing away properly. The next day, same issue again. This is the weird thing. It works correctly sometimes and incorrectly other times. I have a feeling that it will be a classic case of a service call, that when I get someone to look at the problem, it will function as it is supposed to and go back to what it was doing as soon as they leave.

DaveK · Wed Mar 04, 2009 9:25 am

Oh, and Humbly Grateful, by the way...

Robert · Wed Mar 04, 2009 3:27 pm

Hi Dave,

Those calls do happen and irritate the service techs also and are very hard to diagnose.

Takes some patience, isolating circuits and and one by one determine the fault.

Clean flame sensors with steel wool, but htey are usually ok besides being oxidized somewhat.

Keep us posted, maybe it will act up and an hvac tech can come quickly and see what it is.

Thanks,
Robert