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Discussion Starter · #1 ·
hey guys, Ive been searching and searching for an answer before posting, but tonight it is 5 degrees and I give up. I tried to wire this switch up how I thought it should be with no luck and a bit of smoke from the transformer.

here is the story.


I have a 1980s home with an intertherm propane furnace in it, the blower cycles on and off continuously while the burner is still on.
I replaced the one button style limit switch already and that did not help, I am left to believe it is the remaining limit/fan combo switch which is no longer made unfortunately. I tracked down the best recommended replacement part which is a camstat FAL3C-05TD-120-A. This part has only 4 spots for wires, and the old switch has 5 wires coming from it. 40tn33113 is the old part number, and I cant seem to get photos to load. I am a mechanical engineer, but cannot figure this out and have already had the only service guy out here that comes up this way. I live in the mountains of CO, nobody serves my area. We are getting cold up here, so any help is very appreciated.
 

· In Loving Memory
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okay. So now you also need a new transformer.

On the old switch. Is there a drawing that shows a coiled line? If so, that is the heater circuit that aids in bringing the fan on. And is probably what went out in that control.

If the new one doesn't have that coil. Don't connect the wires that went therre.

That type of Cam stat is still made.
 

· In Loving Memory
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Camstat, FALTS57C05T120A. Should be the one you need. Brings on the fan by time or temp. Is yours a 7" insert.
 

· In Loving Memory
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3" is the problem. Not sure it comes in a 3".

Honeywell has the L4064W, that comes in a 5". Not sure it will fit in teh space you have though.
 
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