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toolman5252 · 02-01-2006, 10:38 PM

I have an old dura-therm propane furnace , probably an early seventies or late sixties, no electricity or blower or circut board . It worked fine untill a few days ago. It seems like a real simple unit and it is driving me nutz. The pilot lights and stays on , when I turn the knob to on , it flares on, runs for a few seconds and them groans a bit and goes out, a couple of times it would stay on for a couple of hours if I only turned the knob aprox. half way to on, now it doesnt do that. it gets gas and then seems to run out. Ive cleaned the pilot nozzell, adjusted the pilot, removed a few kinks from the gas line, installed a new thermalcouple and made sure it is in the pilot flame, Ive disassembled it and cleaned out all the dead rodents and bugs, Ive made sure the propane tank is full, Ive checked to be sure it is almost level. My magic chef oven , right next to it works fine, Ive shut that off to possible increase the preasure to the furnace with no success. Im in alaska , its 4 degress outside, Im a week from any parts i may need and two weeks from a new furnace. My question is , does anyone know of any quick fixes, fixes , or bandaids that may make this work? Sorry about the wordyness , Bob

lewster · 02-02-2006, 06:17 AM

Toolman,

I'm not familiar with your unit, but these are some basic tests. Even though you have a new thermocouple, it might not be working. If you have a VOM, you can chack it by heating it with a lighter and see what millivolt reading you get from it. Also, it might be a faulty gas valve in that it is not staying open when it senses the signal from the t/couple. It that case, you would need a new gas valve.

Are you holding the pilot on long enough to completely heat the t/couple so the gas alve knows that it is 'on' ?

Hope this helps.

toolman5252 · 02-02-2006, 06:56 PM

Thankyou for replying , the pilot will stay on all day long as long as I dont turn the knob to on . Something else i did today, that made an improvement, was to take it apart and reseal all the gaskets and remove the small screen from the gas inlet line, and take the gas valve apart and make sure there was no obstructions Now it will light and stay on for aprox. 10 minutes , then sputter , groan and go out. It will relight instantly, go another 10 or so minutes and then go out again with the same noises. I've watched it and when it starts groaning , it apears to run out of gas, but I can put a lighter on the light port and it will fire back up right away, go another ten minutes and then go out again. Was any of that any help or did I just make it work a little better by sealing the gaskets ? Thanks again for your reply , bob

lewster · 02-03-2006, 06:06 AM

Bob,

Have you checked your gas feed line leading up to the orifice and the orifice itself for any obstructions? Just last week I had 2 fairly new furnaces that were either NO/OP or doing a similar pattern as yours, and after dis-assembly, found insects in the gas line and burner orifice.

Cleaning the orifice is a good idea anyway. Be sure to use only compressed air, carb cleaner, etc to clean it. Never but anything into the orifice opening as this is a precision drilled hole and any ateration will negatively effect the unit. Maybe a tooth pick, but nothing metal.

WayWard Wind · 02-03-2006, 09:34 AM

Sounds to me that it's either has a hole or small crack, in the venting system & or gaskets or the vent is partialy obstructed, causing the main burner flame to "float" which causes the pilot flame to go out & then the safety shuts down.
Best,

rtaylor537 · 02-03-2006, 02:23 PM

Is it possible that the propane gas regulator at the tank is malfunctioning. Sounds somewhat familiar as I had a problem with my furnace until I had the regulator replaced. Turned out to be a defective pressure regulator on a relatively new unit.