# new problem.......smoke coming out of the vents!



## Cysnake (Apr 17, 2012)

This is the second time in a week. First time i believe.was the.blower capacitor. The cap was dead and the blower motor ran in reverse for about 8 hours. The house filled with smoke, but didnt set off the detectors, or the co2 detectors. I replaced the cap, over a week ago and all has been good until now. The furnace seems to get too hot. The new fan limiter switch is screwy, but is mostly working. It will turn on with the heat pump and run when the furnace kicks on, but as soon as the furnace kicks off so does the blower fan. It doesnt run to cool the furnace down. Could there be build up of heat and smoke in the vents and when the heat pump kicks up the blower back on blow it up through the vents? The house literally fills with smoke.


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## beenthere (Oct 11, 2008)

Well. You need to address the improper working of the fan limit switch first. And yes, the heat exchanger is probably over heating if the blower is shutting off when the burner shuts off.

Can you take a pic of the heat exchanger area where the fan limit is installed. Probably need to shine a flashlight in the hole to get a good pic.


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## Cysnake (Apr 17, 2012)

Even with the blower running, it heats up the pipe in front so much that after 5 munutes, you cant touch it. It just radiates so much heat. Now im getting the smoke coming up. But its not every time, i cant seem to replicate the smoke, it jusst does it occasioally


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## carmon (May 8, 2010)

I would call a contractor before your next visitor is the fire dept..


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## Cysnake (Apr 17, 2012)

Already there, had 2 guys come out today, and another one coming monday. Going to replace the entire system, and unfortunatly probably all the ductwork as well. Any hvac guys on here around pittsburgh wanna come out and take a look and give an estimate?


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## how (Feb 26, 2011)

The duct work is being changed as well, why????
Is the pipe in front, your vent pipe. It *should* be too hot to touch.
You were asked for a detailed picture of the fan/limit wiring to see if it was hooked up properly. All kinds of photos have put up except whats asked for???
Your blower runs backwards when the capaciter dies???
Anyone else ever see a motor run backwards for that reason???


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## Cysnake (Apr 17, 2012)

Ductwork is not sized properly, and is run incorrectly. To put it plainly i have asbestos wrap on some of the ductwork, and it will not be efficient for a new system. My heating and cooling has always been terrible. My return is way undersized as well.
The motor ran backwards because i wasnt paying attention when the cap died. I spun it by hand to get it going because it was running constantly anyway, and didnt realize i spun it backwards, so it ran backwards for about 8 hours while i slept.


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## Cysnake (Apr 17, 2012)




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## Cysnake (Apr 17, 2012)




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## how (Feb 26, 2011)

I compared the cam stat photo with the cam stats I have and the wiring set up looks correct. The partial shield in temp hole looks like the cam stat might not see enough of the exchanger heat to operate properly. A preheating camstat would probably have been the solution to that by automatically turning on the fan a couple of minutes after the thermostat came started calling for heat.
All moot now.


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## Cysnake (Apr 17, 2012)

That was my thought, the ol one had the bars at the end that wouldve gone up over and allowed it to get more heat. Didnt really think about that till after the fact.


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## beenthere (Oct 11, 2008)

A 5" L4064B would have worked for it. 

The heat exchanger probably had a weak spot in it, and it finally left loose.


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## Cysnake (Apr 17, 2012)

5" wouldve been too long, i only had 3" thats why i had to go with camstat. I wanted a honeywell, but they didnt have one small enough.


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## beenthere (Oct 11, 2008)

Cysnake said:


> 5" wouldve been too long, i only had 3" thats why i had to go with camstat. I wanted a honeywell, but they didnt have one small enough.


5" would have gone past the baffle, and responded faster to heat rise. makes no difference now.


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## Cysnake (Apr 17, 2012)

I put a tape measure in there, everything is too close, 5" wouldnt have fit, the "fins" behind the baffle are too close.


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