# sticking limit switch



## PoleCat (Sep 2, 2009)

Just lit Ol Smokey up this morning and all went well until it was time for the fan to turn off. I gave the Honeywell limit switch a thump and off she goes. Next cycle the same thing. Then again. Any fix for this or do I need to get a new one? The lightest tap triggers it so it makes me think it may be salvageable.


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## yuri (Nov 29, 2008)

Nyet. They get weak with age so buy Ole Smoker a new one for a early Xmas present.:yes:


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## PoleCat (Sep 2, 2009)

When I turned it on this morning the dadburn thing worked right for the first cycle and I was sure the furnace fairies had come in the night. But the next cycle she stuck on again.


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## yuri (Nov 29, 2008)

I thought it wuz supposed to be "dadgum" thing.:yes:

Ever watch Porter Ridge? Terry is pretty dadgum hilarious. check the Terry stays level headed clip. I hate snakes too.

http://dsc.discovery.com/tv-shows/porter-ridge


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## PoleCat (Sep 2, 2009)

This is an older 4046 and the little dial that you're not supposted to rotate was showing 110 at the index after I had pulled it and it cooled further from the standing pilot heat. I knew ambiemt was mid to low 60s so I moved the on and off set points about 40 degrees higher and it is working fine now. Plus I rotated the dial just to be a dick.:laughing:


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## yuri (Nov 29, 2008)

and now you may have a completely unsafe and inaccurate limit control which may kill ole smokie. those controls lose accuracy with age as the copper bi metal spring hardens. it may now go to 300F before the limit shuts off, if at all. the limit is a critical safety device so the control should be replaced for safety reasons. we don't want to read about you and ole smokie in the news.:no:


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## FClef (May 5, 2013)

Those old dial limits have a bimetal temperature sensor coil. That metal will weaken with time. You will eventually have the same problem again, no telling when that could happen.

Limit switches are not expensive. Be kind to your old pal and get him something brand new to play with.


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## beenthere (Oct 11, 2008)

Best thing to do is replace old smokey.

If you don't want to do that, then replace that failing L4064 fan and limit control. Cause its going to either fail again. And next time it could fail that the blower doesn't come on.


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## yuri (Nov 29, 2008)

I saw a limit fail once. Strange what can happen to that plastic drain pain of the ole AC coil. Molten blob of plastic it wuz.:whistling2:


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## beenthere (Oct 11, 2008)

yuri said:


> I saw a limit fail once. Strange what can happen to that plastic drain pain of the ole AC coil. Molten blob of plastic it wuz.:whistling2:


Yeah, and they stick to teh heat exchanger, and really smell up the place for a while after wards.


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## PoleCat (Sep 2, 2009)

I don't know if age caught up with it or it was cooked to death. Toward the end of the last heating season the high limit was turning the burner off several times a cycle and I ended up having to cut open the plenum and clean off the underside of the A coil. Completely coated with a nasty felt. Never turned the heat back on at that point as Spring had sprung. I did make some substantial improvements to the return air duct and filtering though.

I still intend to replace the control when we get past the unexpected 10K in medical bills that popped up over the last week. As Smokey is getting up in years and may not make it another 42 years I was looking to find a bottom dollar replacement part rather than the gold plated jewel encrusted Honeywell number. Any recommendations on what and where ?


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## beenthere (Oct 11, 2008)

Honeywell and White Rodgers are the makers of that stye of control.


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## yuri (Nov 29, 2008)

my local HDepot had them. around $50 I believe. should be under $75.


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