Thread: Question about part for wood furnace.

alright i know im a noob but i have no controls. the only thing i have is a used squirrel cage blower and a limit switch that turns whatever i have on it off at 190 which needs to be my draft blower which i dont have. now im hunting for a affordable limit switch for the main fan. all those honeywell deals are 60 to 70 bux . then when i get that ironed out i need to find info on the draft fans for the firechief and try to locate one of those then i need to start on the ductwork side of the system. i know i feel like i got in over my head but im making progress its just slow. at least i have the flu and chimney installed and all to spec! thanks again for all the help. josh

ya know what? i was looking at one of them and they said they have a "thermostatically controlled draft"....i read that here at the bottom of the page:

http://www.h2oasisinc.com/Fire%20Chi...Add%20ons/135/

i wonder now if that's what that does.........i gotta look into this more.

hey...brainstorming is how to solve problems...and lord only knows, forums are the best place for brainstorming.....lol

from what i understand i will wire a thermostat from in the house to the forced draft blower but with that 190 limit switch in line with it so that it will force a draft when the house demands more heat but yet when the plenum hits 190 the limit switch will shut off the blower and then the main blower will run off a different limit switch to turn on at whatever temp and off at another lower temp say 140 on and 90 off? thats how i understand this is designed to work. but now i just gotta find the parts and pieces as the only thing i have is the main blower and the 190 shut off limit switch. thanks. josh

Originally Posted by ttopmustanggt88

from what i understand i will wire a thermostat from in the house to the forced draft blower but with that 190 limit switch in line with it so that it will force a draft when the house demands more heat

ok, if that be the case, then that switch may be for a 24 volt line, since i doubt your thermostats are line voltage.

but yet when the plenum hits 190 the limit switch will shut off the blower and then the main blower will run off a different limit switch to turn on at whatever temp and off at another lower temp say 140 on and 90 off? thats how i understand this is designed to work. but now i just gotta find the parts and pieces as the only thing i have is the main blower and the 190 shut off limit switch. thanks. josh

it should work that way...you're on the right track.

Originally Posted by ttopmustanggt88

alright i know im a noob but i have no controls. the only thing i have is a used squirrel cage blower and a limit switch that turns whatever i have on it off at 190 which needs to be my draft blower which i dont have. now im hunting for a affordable limit switch for the main fan. all those honeywell deals are 60 to 70 bux . then when i get that ironed out i need to find info on the draft fans for the firechief and try to locate one of those then i need to start on the ductwork side of the system. i know i feel like i got in over my head but im making progress its just slow. at least i have the flu and chimney installed and all to spec! thanks again for all the help. josh

Check out a HVAC installer they may have taken an old gas or oil hot air furnace out. It should have a plenum contol for your blower complete. Check inside the old furnace for a schematic diagram to get an idea as to how it should be wired.

Originally Posted by timbrjackrussel

Your thermostat up stairs would normally be wired in series with the draft control motor or fan or contol relay primary with a plenum high N.C. limit about 190F wired in series with the low voltage control transformer primary black wire, not the plenum fan motor. The plenum fan should be able to start any time the plenum gets up to about 180F and shut off at about 140F. What is the GREEN wire? It should ONLY be used as a bonding , ground .

My setup has no draft inducing blower or limit switch. The two controls only operate a blower relay in the oil furnace. The oil furnace's blower serves as the plenum fan. The draft control is an adjustable bi-metal damper circa 1950's.This setup works fine with no power. I only added the controls to increase efficiency and to better circulate heat on the main floor.
When the wires outside blow down my house stays toasty warm without needing to fire up the generator.
I didn't give a crap what color the wire is it only 24vac and runs 4 feet. Plus the blower almost never runs as this system uses natural draft for combustion and convection for circulation.Thankyou timberjackrussel for your concern.

No burning of OPEC juice was required to heat my home this winter.

With the location of the forced draft, that unit could get very hot very quick. Mines above my fire not on it. It would help as far as heat demand, but wood consumption will quickly rise. Mine has a squirrel cage blower, that mounts into an adaptor for the pipe plug in the back. I keep mine set for 68 and my lp furnace for 65. My gas furnace hasn't ran yet this year. I went out buying a forced draft for my furnace a couple of years ago. I must say now that I shouldn't have. Most of the time I keep mine off. But like I said if it drops down below 68 then it will pressurize the firebox and up the draft, therefore kicking on the limit control. Mine is set for 145 on and 85 off. My limit is 170. I have yet to see my furnace limit out to 170 with the forced draft. Some forced draft motors have a damper that open and closes on demand. Mine doesn't. Here is a pic of mine.

Good news my dad had a old furnace laying around that he said he was gonna trash so i stole the thermoswitch out of it and it works great. now i just have to find the pieces needed for the duct work and ill be heating the house with wood. slowly but shurly getting closer. thanks for all your help.josh

Grab the blower and motor and any thing else that looks like they may be useful.

dont worry i gutted it never know when ya might need another squirrel cage blower or limit switch.

problem with thermoswitch i reliezed that this thermoswitch isnt working as i though it would. the switch turns the fan on at the lowest setting no matter how i wire it. right now i have it wired with the yellow and black which is on the fan side i have those breaking my power side on the fan motor. this unit has a yellow and black on the fan side and a pink and red on the limit side. maybe im doing something wrong but i thought that this thing would turn fan on at my high setting and then off at the low setting? i have a few pics of it if anyone knows anything about these any help would be appreciated. thanks again josh.

Move the wires out of the way and take the picture again so I can read the words on the switch. Usually a hot feed in, that is closed to another when operating temp. is reached, opens this pair when temp. falls, this would be the feed to your large plenum blower, and another normally closed contact between the hot feed in and the upper limit that would shut off power to the draft fan or draft door opening motor if the plenum was too hot.

Likely the left side pair are the operators for the plenum blower, bottom one hot and the upper to the blower hot. Are the 2 bottom ones still joined with a link? It may say break link for low voltage. If the link is still there then the top right would be the upper limit hot feed to a 120V AC circuit for the draft fan or draft door motor control transformer. Need to know the voltage of this circuit. Usually the upper limit feeds the primary (120 VAC) of the thermostat transformer, then the thermostat on the low voltage side (24VAC) would control the draft door opening motor(24V) .

Heres a better pic I have the Plenum blower hooked up to the fan side and it works but not like i thought it would i thought it would keep an open circut till the tem got to the middle needle which is at 140 or so in the pic then turn plenum fan on till it got to the lowest needle or the one furthest to the left which is on 130 or so now just for testing. but this switch turns on at the lower needle nomatter what i do. as for the limit side i havnt played with that yet because i dont have a draft fan yet or a thermostat in the house to run that so i havnt played with that side yet but as far as i understand it should cut power at whatever the third or last needle is set at. there doesnt appear to be a jumper whatever thats worth. thanks a million. josh

There seems to be a big difference in the position of the dial in your pictures. I hope that you are not turning it. It says, Don't turn dial when setting pointers. Only use a heat gun to warm up the sensor for testing. Move the fan operator tabs apart then see if the circuit on the left side is still closed. It must be open at room temp. 7:30 AM here and I am loading up 066 and splitter to get to bush. About 6 128 cft. cords to start at, -5 degrees C. perfect for working No bugs!!!