Question on older wood furnace

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.

Sono

Member
Dec 22, 2021
62
Mo
Hi everyone, Got a question about wiring diagram for an older stand alone wood burning furnace. My father in law bought a 60 acre property with a hugh pole barn that has a wood burning furnace which he did some tinkering with and screwed stuff up. I am not familiar with the wiring for it so I wanted to ask before I short something out. I know electrical but I dont know about this set up. It has 2 boxes on the side, one is what I guess is the limit switch to set the cut on and off temps which has a long spring-like rod on the back that feeds into the furnace, next to that is another box that has a transformer ( I dont know if it is a step down 12 or 24 volt ) then at the bottom is a large squirrel cage blower (120v)
Would anyone have a diagram for wiring this, it seems basic but I just dont know what goes where as he is old and destroys everything he touches, just trying to get his heat going for him. This is not a picture of his setup, just something I found generically, but simular. Thanks for any help.

th (14).jpg th (13).jpg
 
What brand/model is it?
The wiring on most of those is pretty simple...you have the idea, that is a Honeywell limit switch and controls the blower on/off, also cuts off power to any draft door/inducer on over temp conditions...and transformer should be 120v to 24vac...
 
  • Like
Reactions: Sono
What brand/model is it?
The wiring on most of those is pretty simple...you have the idea, that is a Honeywell limit switch and controls the blower on/off, also cuts off power to any draft door/inducer on over temp conditions...and transformer should be 120v to 24vac...
No clue, nothing on it. All there is , is the blower to blow heat from bottom out the top. Supposed to start blowing at a set temp and shut off the blower once shop is heated and cycle as temp permits. I just have no clue what wire goes where and for what as Ive never messed with one before. Very simular to this one

302150519_5557402237706358_7141413973742068375_n.jpg 302438791_5362449190516560_4007535458784848343_n.jpg
 
If you get really good pics of the components/wiring, we might be able to piece things back together, maybe?
I'm familiar with the Honeywell fan control/limit switches, but there are different ways they can be wired, based on what you are working with exactly...and you could have 2, 3, or 4 wires going to it. (even more in some less common cases)
 
Sounds similar to my 1984 Brunco. We'll need pictures of the wiring boxes and any nameplates to get you any useful information. The components on these old furnaces are usually searchable online and can be figured out.
The high voltage box will power the circulating blower when the temperature gets to a setpoint - usually adjustable. If there is a draft blower as well, the wiring is more complicated and uses a thermostat.

PSA to not store oil that close to a wood furnace. :cool:
 
Pic is too blurry to read the letters on the load door. That would probably be the brand name to Google a manual for. Otherwise it could probably be wired like any Clayton or US Stove HotBlast. Those parts are basically the same. The only thing that may be different is some have a motor that controls a flap on the air intake and some have a draft fan that blow air into the air intake. If his doesn’t have those just ignore that part of the diagram.
 
Pic is too blurry to read the letters on the load door. That would probably be the brand name to Google a manual for. Otherwise it could probably be wired like any Clayton or US Stove HotBlast. Those parts are basically the same. The only thing that may be different is some have a motor that controls a flap on the air intake and some have a draft fan that blow air into the air intake. If his doesn’t have those just ignore that part of the diagram.
as stated these are not actual pictures of it, Just a referal to what it basically looks like.
it is 110v for sure. What I do know by memory is 110v runs into the Limit switch then out to the transformer then down to the blower motor. There is no damper motors or anything else to be wired.
He screwed something up as he didnt draw or take pictures of it before he messed with it ( he tried to add an outlet jumping off the power ) then couldnt figure out what wires he took off from where so just wired the blower directly and he wants to have it back where it runs as temps allow again. Being I dont know about the limit switch nor the transformer, Im just trying to get the basic wiring to put it back together for him next time I go. It is just the limit switch, transformer thing and a blower motor, I just dont want to short it out and internet isnt showing me anything in my searches.