goodman gmnt100 wont lite - Contractor Talk - Professional Construction and Remodeling Forum

mme · 10-21-2008, 11:15 AM

yes its me again. this goodman is going to be the death of me yet. hers the problem.

Turned power on unit.
(propane was topped off approx. 2 weeks ago)

turn thermostat on to about 75 - 80 degrees

motor turns on
the ignitor glows red
i hear the pressure switch engage
ignitor turns off
powers down

restarts cycle a few seconds later

the only error light i get is the three blinks after the furnace cycles through a few times with failed ignition.

help?
last year I replaced the circuit board.

mme · 10-21-2008, 08:43 PM

okay heres an update. I checked voltage around the gas valve. 25 volts. around all limit switches. 25 volts. one limit switch below the gas valve had no reading at all. Contractor was helping me on the phone he said to jump it but there was still no ingnition. I am getting ready to take the ignitor off and clean it. no sand paper. Any other ideas?

I am slowly beginning to realize that goodman sucks. For a four year old machine it has been nothing but trouble.

Pegleg Smith · 10-21-2008, 11:03 PM

have you checked the gas pressure to the valve abd then the pressure out of the valve? LP has a higher operating pressure than Natural gas.

flashheatingand · 10-22-2008, 12:29 AM

Don't mess with the ignitor. You said it came on, so it's probably ok. They break easily. It sounds as if the gas valve is the culprit. However, that is based on very little info. The parts are under warranty still, but manufacturers do not like to replace parts that work ok. I know fixing stuff is fun, and gratifying, but a Goodman dealer, or any other hvac outfit probably could make kids play out of this problem. Sorry to hear you are having problems, but Goodman isn't a bad company, and they are likely to stand behind their product. But, you need to let them know the problems you have had.

hf05 · 10-22-2008, 06:23 AM

just a thought is the valve turned on. tank open and drop valve open!!

mme · 10-22-2008, 03:14 PM

the gas valve switch is on and the propane tank is open.

Drop valve? not sure

At this time getting a pro is out of the question. Been laid off and money isnt there. No contractor will work with me. LOL. Ive even offered to be their grunt to pay it off. no luck. so I have to do this myself.

flashheatingand · 10-23-2008, 09:18 AM

How much time lapsed between the time your propane was topped off and the problem with the furnace?

mme · 10-23-2008, 05:48 PM

thanks guys I got it fixed. I misread a reading on one of the limit switches. the one located on the squirrel cage. (Fan) reading going into it was 25V outgoing was 56v. Repairman that was helping me via phone said thats it. I jumped it and yipppeeeee. we had light.

So check and double check your reading guys/gals. Simple to make a mistake.
now i have another question anyone good with ductwork. Existing ductwork isnt cutting it.

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