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shoesvw · Oct 28, 2009, 09:19 AM

Hello !
I am an auto mechanic, so when it comes to furnaces, I know nothing, but I have been learning about my furnce today.
I have a goodman GMP-150-5 furnace that when the thermostat turns it on, I haer the draft fan start and run and after about 5 minutes, it just shuts down.
Now, I looked at the ignitor which looked fine, but since it was not glowing and this is a common part, I replaced it with a new one (That was no help).
I checked the fuse on the circuit board (good), and found out about the diagnostic codes. (The diagnostic code is flashing 3 blinks - would this cause these symptoms with the draft fan running and no ignitor glowing ?)
I am going to remedy the problems shown by the diagnostic code, but I am unsure if there may be another problem since the ignitor is not glowing and I have 2 children coming home from school to a home with no heat, so I want to make sure I don't replace anoher part un-necessarily and still not be able to make it run.
Thanks to anyone who answers this!

hvac1000 · Oct 28, 2009, 09:50 AM

Look on the inside of the furnace blower for the code's or blink code. It will tell you the most likely place to start.

shoesvw · Oct 28, 2009, 01:59 PM

Thanks for your help !
There has been some progress - I cleaned out the bottom of the chimney (dirt nearly blocking the flue). The new problem is the ignitor now glows, (It didn't before) but no gas flame.
I did a little poking around with a continuity meter and I found one of three heat sensors (don't know if this is the right term? ) has no continuity through it (This is a small metal unit with 2 wires on it, there are 3 of them mounted by the burner - one on top and one on each side-the wires run through all 3 of these, and it ends up at the gas valve).
Since 1 of them was defective, I jumped across it and everything worked, but the burner got so hot it started melting the wires above it.
Is this still a draft problem ?
Thanks for any help!

hvac1000 · Oct 28, 2009, 02:24 PM

You bet it is and right about now you should be calling for a On Site inspection from a professional before you destroy the furnace and possibly yourself.