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Kissfan4 10-09-2012 08:52 AM

Gas furnace problem
Ok so I attempted to turn my furnace on last night since it was going down into the 30's and when I did nothing happened. So I went into the basement and had my fiancÚ turn it back on, the small blower motor starts, then after a short time the pilot lights starts to glow( this is not a flame but just a piece of metal that glows orange like a glow plug) then when're whole thing shuts down. I know the problem is that the gas valve is not opening but how do I tell if it is the valve itself that is bad? There are two wires I believe that connect to the valve, a blue one and a purple one that connects to small circular things that surroun where the burners are. Please don't just suggest calling a tech. Money is extremely tight and I just can't afford to do so. Thanks

carmon 10-09-2012 08:55 AM

measure voltage at gas valve.. also insure gas is on to furnace.. should get 24 volts to gas valve....:thumbsup:

ben's plumbing 10-09-2012 09:39 AM

there is also and on and off swicth for the gas valve on the valve it self...make sure it on...had to ask....ben sr

Kissfan4 10-09-2012 09:40 AM

is the purple wire the ground? without looking at a schematic i am assuming the purple wire i see that connects those plugs ground the valve, and if the fire comes out to far it breaks one of those plugs and causes the valve to close. sorry for the terminology but i dont know what those things are called lol

beenthere 10-09-2012 02:23 PM

Look for small buttons in the middle of the small circular things(roll out switches), its a reset, try pushing them in. If one or more of them resets. then watch as the furnace runs and see if the flames change when the blower comes on. If so, you probably have a cracked heat exchanger.

PS: Stranger things have happened, so are you sure you have gas.

Kissfan4 10-09-2012 04:43 PM

Yes to the gas, I am going to check the roll out switches when I get home

Kissfan4 10-10-2012 06:06 AM

ok, so i think i have it narrowed down to the gas valve, the board was giving me 2 or 3 error codes so i checked them and each code eventually refrences back to the gas valve. the only thing im not understanding is at no part during the startup do i measure any voltage to the gas valve. if the gas valve is indeed stuck would the furnace still send the voltage to open it?

ben's plumbing 10-10-2012 06:43 AM

what is the make of your furnace.....does it have the honeywell smartvalve system.....after reading your last post if you don't have voltage to valve perhaps it a bad relay on board...proving to be bad control board...ben sr

biggles 10-10-2012 06:59 AM

if you had 24Vs at the valve then the valve is aced :wink: the board isn't sending the 24V read the board where the valve wires connect..see if you have 24v there...your not even getting pilot gas first off

how 10-10-2012 10:19 AM

If you are getting 24V to the gas valve, it should be opening.
I am not sure from your description if you actually have a pilot flame system or if its a direct ignition system for the main burners.

A photo would also confirm that we are not dealing with a smart valve?

Kissfan4 10-10-2012 11:10 AM

there is no pilot light, it is a heating element that when triggered it glows orange to ignite the gas, i do not get the voltage to the gas valve so i am now begining to believe it may be the relay on the control board. when i get home tonight i am going to tap on the relay to see if maybe i can get it to close

Flyers28 10-10-2012 11:50 AM

You have a hot surface igniter. It will glow and then you should hear a click from the gas valve. If there is no click the check voltage to gas valve.

beenthere 10-10-2012 03:14 PM

Did you try resetting the roll outs.

Kissfan4 10-11-2012 06:26 AM

i did reset the rollouts, i know for a fact they are good, i never do get 24 volts to the gas valve. I can not find a wiring diagram for the control board, which i think is what is wrong with it, to find where the 24v comes from. i kow it is supposed to come out on the purple wire but thats as far as i can troubleshoot it. the furnace is a goodman, Model #GMPN120-5 Revb

Flyers28 10-11-2012 11:02 AM

Check the 24 volt transformer inside the blower cabinet. Also check the fuse on the circuit board if it had one.

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