Floor Furnace Help


Old 12-26-08, 10:39 AM
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Floor Furnace Help

I have an old floor furnace in my house.. Christmas eve the heater stopped working. The pilot is lit but the burners will not ignite. I have removed the thermostat and conected the two wires together and the burners will still not ignite.

The pilot looks a little funny. there is one large blue flame coming out of one post and there is another post with a small tiny yellow flame on it. I tapped on the pilot a few times and tried to clean the post with the small flame. After I did this the burners would turn on.. But then an hour later it stopped again. And now not matter what I tap on or try, it will not come back on.

Please help.

Last edited by rtdolfan; 12-26-08 at 10:41 AM. Reason: notification chance
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Old 12-26-08, 02:01 PM
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You obviously have a pilot problem and you'll need to take out the pilot assembly and clear the tiny orifice hole.
Old 12-27-08, 07:03 AM
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How is the orifice cleaned out without enlarging it or damaging it? Do you use a piece of wire or is something else better?
Old 12-28-08, 11:07 AM
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I would guess you have a PG-1 pilot generator. The flame you see below most likely is coming from the primary air opening. You could try blowing thru the hole or disassemble the pilot and clean the dust/lint/spider from the assembly.
Old 12-28-08, 05:27 PM
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Yes, you need to take out and disassemble the pilot burner, which you will probably find plugged with crud (trademark). Clean the pilot orifice with the wire from a wire brush.

After you get it working, take the grate off the top of the floor furnace and pull out the sheet metal that surrounds the heat exchanger and clean all the dust and crud out of that --- something which usually accumulated over a few decades without being cleaned.

Use a vacuum to clean out all the junk.

Also--- inspect the burners, heat exchanger and venting system for cracks or plugging. These are usually old units. They too often don;t get adequate maintenance and can be a hazard because of that.

Frankly, I'd look around for an honest an competent repair serive which will do this cleaning and maintenence for you without trying to sell you new equipment unless there is a real reason for doing so.

Good luck with finding such a person.
Old 01-02-09, 10:53 AM
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Getting floor furnace main burners to stay lit

Assuming your floor furnace is similar to my 60-year-old Louisville Tin & Stove unit ****** there may be another check to make before going under the house to check the pilot burner as suggested earlier.

First, most floor furnaces operate on self-generated millivolt power. Unlike forced air systems with electric fans or oil burners with electric pumps, this incredibly simple and generally reliable system enables you to have heat even if you have no electrical power. The lit pilot flame heats a thermopile (AKA powerpile or thermocouple), which generates about 500 millivolts (one-half volt) of electricity.

In my furnace, there are five electrical components and the wiring between them. There is: (1) the thermopile that generates electricity; (2) the thermostat that measures temperature in the house and "tells" the heater (by closing the circuit and allowing current to flow) when to turn on the main burners; (3) the valve that opens in response to the thermostat, allowing gas to the main burner that is ignited by the pilot; and (4 and 5) two limit switches (AKA limiters).

The limit switches open (stopping current and causing the valve to shut) when temperature inside the heater casing reaches a certain level. My limiter switches often stick open -- preventing the main burner from coming on -- and a quick rap or even just banging the floor beside them will allow the offender to close at least for a while. If the problem comes back, replacement is easy on my system because they're just below the floor grille. That placement also makes them easy to test.

To test a limit switch, just disconnect the leads from each side and connect those leads directly to each other. A jumper wire with alligator clips is best, but you can do it by just holding them together metal-to-metal. Wait a minute to give the valve time to respond, millivolt systems are usually a bit slow. If a cool system fires up when you jump the limiter, but not otherwise, replace the limiter. To reduce unneeded wear on my old back and knees, I like to jump out both limiters and the thermostat all at the same time before crawling under my house.


Good luck!


Last edited by Shadeladie; 12-10-11 at 07:34 AM. Reason: Links removed

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