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furnace cutting out


cabezon

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Hi all,

I'm the proud owner of a 1985 New Horizon. Had it about three months, and it's been fun. Some wrinkles to iron out, but that's to be expected.

I've been in some cold country of late, and I can't seem to get the furnace to run consistently. I can get pilot to light, stay on, and fire up the furnace. But sometimes it will just randomly cut out while burning. Or, when it shuts off from the thermostat, that will make the pilot light go out too. Those seem to be the two main instances.

The gasket on the little door in front of the pilot was trashed, so I replaced that. Before I did that, the pilot was blowing out every time the furnace kicked on, presumably because of a draft. Could that still the problem? It seems odd that it will sometimes cut out while in full burn mode.

Any help is appreciated. Thanks.

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Hello,

I was reading about Propane on some of the other RV sites about the same kind of problem you

are having and some of their problems ended up being a bad tank valve/regulator, and a bad

batch of propane (moisture in the propane).

Hope this helps,

Dennis...

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Turn on one of the burners of the stove and monitor it to see if it also blows out or changes color. This should give you an idea if its bad Propane or a frozen Regulator.

If this is OK and its going out when the burner is lit.

Does that furnace have a Pilot Light?? (I assume it does as you've mentioned it a couple times)

You say "Cuts Out", doe the Pilot light cut out also?

Possible Thermocouple bad or not aligned in the flame correctly.

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Thanks for the input. I thought it might be a bad regulator, since it looks old and is probably the original. The flame from the stove seems fine though, steady and blue.

When the furnace goes out, it's usually while running, and both the burner and the pilot go out. Is the pilot required to keep the burner going while it's on? I just assumed once it was lit it would stay lit until shut off.

Thanks.

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I would say if the stove is OK, your propane system is probably OK.

The Thermocouple needs to detect heat all the time or it closes the fuel valve (Safety Feature). If you light the pilot the thermocouple should be just barely touching the pilot flame. I'm not sure what your exact setup is, but if its posible for the pilot flame to be blown a little and moved away from the Thermocouple, this could cause it. You might want to make sure the thermocouple is sitting nicely in the pilot flame.

What model furnace do you have?

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Does it really have a pilot light or is it the more standard spark lit type? What Brand and model?

There are several things to check. One is the thermal cutout switch, if it gets too hot it cuts off the gas, usual reason is due to poor air heat circulation, the switch probably mounted to the heat exchanger. Second reason is too high a gas pressure, but you should see too high flame on stove also. Third reason is burnt out burner plate allows gas to shoot past burner grid too fast to maintain flame. Fourth reason is sail switch not staying on thus shutting off gas. Normally the thermostat tells the fan to start blowing, the sail switch then turns on after a delay, then after another delay the gas valve opens (it clicks), and then a short delay after that the sparker lights the flame. It continues to burn until the thermostat says it is warm enough, which turns off the gas but the fan continues to run until it has sucked the residual warmth out of the furnace. You could also have a funky circuit board, it handles the gas valve and spark lighter.

Could be something else, but need the ID of your furnace to know.

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Thanks for all the info. The furnace is a DuoTherm 66117-006. It definitely has a pilot light, with a sparker on the side to light it.

I'm assuming the thermocouple is the cylindrical thing that sticks into the bottom of the pilot. It's sitting in the bottom edge of the flame, but seems like it ought to be hot enough to detect the flame.

The fan runs great, and I can's see any holes in the metal burner plate. It seems to work like it should, i.e. the fan comes on, then the gas kicks on after a few seconds.

It's actually been working better lately, so maybe it's fixing itself. Always nice when that happens. The thermostat seems to work fine too. I'll run it more today and see what happens.

Thanks again.

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Generally, things that fix themselves always break themselves, at the worst possible time.

see if you can reposition the thermocouple so its a little higher up and more in the flame.

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