Furnace Won't fire

[ktull]

I've been having difficulty with a furnace. Unfortunately I'm not at home and can't remember the specifics(manufacturer, serial #,etc.). It's a late model gas furnace. The problem is that the thermostat will be set to heat. The furnace will turn on, the pilot will light up, I'll here a clicking sound and then thhe burners won't fire up. The problem is intermittent, so when its working, the burners will light up after the clicking sound. I've replaced the thermostat and the main circuit board, and the problem still exists. Any thoughts on what could be causing this? Please help.

[Bubba]

Id try the gas valve next. If that doesnt work, try the fan & limit switch. Next install a new transformer. Then get a new flame sensor. After that, install new burners. Then try a new blower motor. After that you should only have a few more parts and you will be set. Bubba

[Edwin Pawlowski]

My first place to check would be the gas valve. They sometimes stick and do not open. I'd also look at getting a quick lesson on how the heater works so you don't waste money the first time around.

[almoran]

Just keep throwing parts at it, that will eventually fix it.

[ktull]

Edwin, Thanks for the response. I have more info now. My furnace is a Goodman GMT 070-3. The igniter is lighting up, and I hear a clicking sound, but the burners just won't trigger. Is it a possibility that there is some type of safety mechanism that's been triggered that I just need to shut off? As an aside, my "handyman" replaced the igniter with a universal glo-stix igniter when I first started having this problem. I'm at a loss.

[CBHVAC]

Ive got a serious question for you..

WHY do people ALWAYS replace the thermostat, when 99% of the time its NEVER the thermostat?

That goodman furnace has 7 safety switches on it that could be tripped, (if the right diagram was put in this damn book) and no one here can tell you what, if any, are tripped. Now you are finding out why Goodman, is good to repair folks... Also as a suggestion, dont get a handyman to fix items like your gas fired furnace. IF a safety is tripped, it tripped for a reason, and a tech knows to look and what to inspect if this is the case, while a handyman is handy to press buttons. Thats almost like asking your general practicer to perform open heart.

[Dr. Hardcrab]

Easy. The only thing they KNOW is the thermostat (that's not a put-down. It's reality). They see that it is 60 degrees in the house and they put it on 70. The thermometer doesn't move so it HAS to be broken/bad. Then they think "I can change wires!" I like the ones that come back and say "Now NOTHING works! Not even the fan".

Where can I buy a transformer???

[maradcliff]

First off, is the pilot lighting? If not, nothing else is going to fire. If you confirm the pilot is lighting, I agree with others that the gas valve is bad. However, are there any other safety devices in the wiring circuit? Can you get a schematic? Maybe the manufacturer can email of fax you one. At least that way you can determine if there are any safety devices, and if there are, put a meter on each one.

If however, you are not getting the pilot to light, and ARE getting the needed spark, you either have a bad thermocouple, or gas is not getting to the pilot head. To determine if gas is getting to the pilot head, use a match, lighter or small torch.

One last tip. If the pilot is working fine, and you found all safety devices (if they exist) to be working. Give the gas valve rap with a block of wood when it's trying to ignite. They can stick. (of course dont hit hard enough to break it off). If that gets it going, replace the gas valve. That rap might get it working then, but it wont stay that way.

Mark