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Posted by: Ryflyby Oct 1 2017, 03:42 PM

looking to find a gas valve for my furnace. have heat but thermostat doesn't shut off valve when satisfied. would like to find replacement. Any help would be appreciated. THx

Posted by: 509dave Dec 26 2017, 10:51 AM

I'd try pplmotorhomes.com or tweetys.com...

Posted by: 509dave Dec 26 2017, 11:21 AM

Sorry, I had 'water heater' stuck in my head, not furnace.

Posted by: SidecarFlip Dec 29 2017, 09:07 AM

The sponsor of this site has many for sale, take your choice. Click on the 'RV Parts' at the top of the page....

Posted by: RV_Tech Dec 30 2017, 02:35 PM

Because furnace gas valves have duplex solenoids a stuck valve would require both solenoids to fail simultaneously in the open position, a virtual impossibility since they only open under power. Far more like like a shorted wire or board. If the valve is truly stuck, disconnecting the hot lead to the valve should make no difference, but I bet if you do, the valve will close. I have worked on more than one RV with the same problem, always a wiring or control issue.

Posted by: SidecarFlip Dec 31 2017, 09:36 PM

I just learned something I never knew myself.... I take it the duplex valve is for safety reasons?

Posted by: RV_Tech Jan 1 2018, 07:33 AM

Yes for safety, same with water heater. Actually everything in the propane systems defaults towards "off or lower pressure". For example, has anyone ever seen a propane regulator that puts out more rather than less pressure when it fails? When they get old, they put out less and less pressure, not more.

Back to the furnace staying on, all it takes is mouse chewed wires to short the two that feed the furnace from the thermostat to keep it going and that is a common cause. A staple through the wires will do the same thing.

Want to test for it? Go right to the side of the furnace where the thermostat and power comes in. Disconnect one of the blue leads from the thermostat wire. Did it end the runaway furnace? If it did, it is a thermostat wire issue, not a furnace issue. The furnace is just doing what it was being told to do. Every single component in the furnace is designed to open the circuit and shut down without power. It has to be that way for safety. Makes sense right?