Goodman GCH95 won't ignite

[Saltysakz]

Help help help! I installed a Goodman GCH95 95% nat gas furnace for my mom last fall. Somewhere around last april she complained it wasn't keeping house warm and took a video of furnace. It was lighting when tstat called but would go out and relight and repeat. I checked system and found that it would not stay lit after several heat cycles. At that time (april) I found the gas valve wasn't opening everytime it tried to light and replaced the gas valve under warranty. Now (today) I found that it would light for a few cycles and then not at all. Tstat calls, idm starts, ignitor glows, gas valve energizes - and then ignitor drops out without reading any gas pressure on gas gauge. I took a lunch break and came back and same thing - it lit a few times then I can't get it to do anything other than the sequence aboove. Does anyone have a recommendation as what to do next. I jumped all safeties one by one and ohmed all out. I'm thinking maybe control board. I cleaned flame sensor and pulled orifices. All ok. Please help...driving me nuts!!!

Thanks,
Erik

[HAWK 87]

I dont know how much technical information we are allowed to give in "tech-to-tech". Bottom line, you need to find out where your 24v is dropping out. Is it energizing the gas valve (use your metter, not your monometter)? or dropping out at a pressure switch, ect...

[Saltysakz]

The gas valve is getting 24v but the heat cycle is interupted when the valve doesn't open.

[BaldLoonie]

If you've confirmed good gas supply, sounds like a bad valve.

[Saltysakz]

If you've confirmed good gas supply, sounds like a bad valve.

Yea I know. That's what I thought originally and installed a new one under the warranty. But...here I am with new valve and same problem.

[Saltysakz]

I'm new to site and posted same question in other forum. Sorry, here is my question again.

Help help help! I installed a Goodman GCH95 95% nat gas furnace for my mom last fall. Somewhere around last april she complained it wasn't keeping house warm and took a video of furnace. It was lighting when tstat called but would go out and relight and repeat. I checked system and found that it would not stay lit after several heat cycles. At that time (april) I found the gas valve wasn't opening everytime it tried to light and replaced the gas valve under warranty. Now (today) I found that it would light for a few cycles and then not at all. Tstat calls, idm starts, ignitor glows, gas valve energizes - and then ignitor drops out without reading any gas pressure on gas gauge. I took a lunch break and came back and same thing - it lit a few times then I can't get it to do anything other than the sequence aboove. Does anyone have a recommendation as what to do next. I jumped all safeties one by one and ohmed all out. I'm thinking maybe control board. I cleaned flame sensor and pulled orifices. All ok. Please help...driving me nuts!!!

Thanks,
Erik

[timebuilder]

Let me get this straight.

You said the gas valve IS being energized, and you are not registering gas pressure at the manifold?

[beenthere]

Merged your threads.

[Saltysakz]

Let me get this straight.

You said the gas valve IS being energized, and you are not registering gas pressure at the manifold?

That's correct. 24v is sent to valve but after 1-2 seconds the ignitor is de-energized and the heat sequence starts again with same result.

[heaterman]

Have you consulted Goodman Tech Support?

[jeremyhall.tech.sc]

The gas valve is getting 24v but the heat cycle is interupted when the valve doesn't open.

I'm gonna say no, the gas valve is fine and its a voltage / proving problem.

Check the flue , then PS then , the stat, then the wiring to and from the control circuit
Then you should make a 5 min you tube vid of the problem (include ductwork , flue piping , and video of at least 5 bad start-ups.) Post it then we can review.... the reason I say this is your troubleshooting
Technique isn't so obvious to me and I'm stumped until I get a look see.......................