OT wood furnace

I have a "FRANKS wood/coal HEAT" furnace. The blower won't shut off. The duct blower is blowing. There is no fire in the stove. I shut the blower off because of that. It has a HONEYWELL push on pull auto blower,UL 169H switch on it. I took the box off of the furnace it has a 5" coiled senser. I could not see anything wrong. Limited electrical knowledge here, no testers or anything.
I took the DAYTON 8A02-A5 cover off looked at the "breaker contact points". This is the box that has thermostat wires on an electrical board.I turned on the furnce and took my ball point pen and opened and closed these. It did not effect anything.
Question how to tell which is bad. I think the Dayton box. Please keep replys/ sugestions in extreme laymen terms.
If you know where the best place "price wise let me know also. I am in the Jackson/Ann Arbor Michigan area... Thanks in advance for any advice on this... MTP
 
Most likely the fan Limit contol is not changing states or the button is stuck in manual. The fan limit senses the heat in the air plenum and turns on or off the blower if the button is in automatic.

If the thermostate on the wall is disconnected then most likely the fan limit is the issue. I would pull it out of the stove and take it to a HVAC supply house or Graingers and they can match a new one up for you. You will also have to set the upper and lower limits on the fan controls. If you have limited knolwlage, I'd suggest an HVAC technican may be your best bet.
 
Thanks for the reply. The limit control has been set on automatic for years. I did pull and push it several times. Nothing helped. I am mechanical just not electricaly minded. Never messed with it much. I don't mess with stuff I can't see. Could it be the contact points in the Dayton? It messed up like this a couple years ago. I think I just cycled them openning and closing them. When I powered it back up it was fine...MTP I would like to get the parts before everything is closed down for the 4 day weekend... thanks MTP
 
Mike - I used to have a small wood furnace in my shop that had a Honeywell control like you describe, with the push on/pull auto button it. My furnace did not have a draft blower on it, and no thermostat. The Honeywell control was for the duct fan - the only electrical component on my furnace. I had to fool with it a few times to get it to turn off automatically when the furnace cooled down. Mine had a set screw you could loosen for adjustment. Hope this helps.

Paul
 
Mike, I used to have a wood furnace that used that Honeywell limit switch for the blower. Looks like a helix if you take it out of the furnace right? Anyway, sometimes when mine was gradually cooling down, like a day when a fire was only needed in the morning, that switch would stick on and the blower would keep running. If you smacked the side of the wood furnace with your hand, it would shut off. My buddy that does heating and cooling gave me an old one off from a fuel oil furnace. It worked great up until I sold the stove. The new ones seemed like were about $70, and he said they are all low quality Chinese junk for the most part now.

Ross
 
Thanks for the replies...I did the Ross trick to it. When I hit the furnace it did not help. I spayed the coil senser on the limit control with WD40. Manually working the spring back and forth. It still did not help. Back to hitting the side of the furnace, still nothing stopping the fan. I then did the extreme Ross to it. I took the senser out of the furnace and clunked it againt the floor. That stopped it. I built a fire in it. It is cycling as it should be. Thanks a again for all the replies...MTP
 
(quoted from post at 10:29:20 11/26/15) Thanks for the replies...I did the Ross trick to it. When I hit the furnace it did not help. I spayed the coil senser on the limit control with WD40. Manually working the spring back and forth. It still did not help. Back to hitting the side of the furnace, still nothing stopping the fan. I then did the extreme Ross to it. I took the senser out of the furnace and clunked it againt the floor. That stopped it. I built a fire in it. It is cycling as it should be. Thanks a again for all the replies...MTP




Replace the limit switch. If it fails to turn the fan when there is a fire you run a huge risk of over heating the stove and having a much larger problem than just a fan limit switch control.
 

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