Thread: Question about part for wood furnace.

Ive posted about a furnace i recently purchased and it did not come with all the parts like the blowers and electrical stuff but it did come with this thingy and i believe its the thermostatic switch for the main blower as it fits in a hole in the side of the stove but im not positive and if it is how would i go about wiring it up correctly? thanks for any imput. josh

or a thermal disc. It will wire between your hot(either from switch or stat.) and the blower.
Using a three position switch you can either use this to control off and on.. Or you can have an off.. or you can have an on. by overriding the disc

always wire the black wire to a switch, or, as in your case, to that thermal disc.

never the white wire.

ok so i can go from hot power (black) to one side of switch, then hot black on the other side of switch to the hot black side of blower. and run white directly to blower and that should do it?? what kind of temps do these things normally turn on at?? thanks so much for the info. josh

That switch goes in a high temperature environment.

The electrical wire you use should have high temperature insulation and be designed for such conditions.

There might be numbers on that switch that would give you a clue to it's switching temperature.

there is a hole on the side of the stove that the switch fits in and the numbers on the back are kinda funny heres whats on the back.

312328
T-O-D
8226
L190-20

That should be a 190f switch which seems a little high for a blower switch.It could also be a high limit switch to kill the draft inducing blower in an over temp situation depending on the furnace design and switch placement. Run a test light through it and see if it is closed a room temp - if its closed at room temp it is a limit switch - if it is open at room temp it is an operating switch. Heat it up with a candle and see if it closes at temp.
That furnace should have a model tag on it - call the mfg and get some instructions. It sucks to burn your house down.

thanks for posting that ken that just made my whole day make sense. couldnt figure out why this thing was closed at room temp, thought i had a bad switch but now it makes sense this is a limit switch for the forced draft. now i have to find where i can get a thermostatic switch for my main blower one that comes on at 140 and off at 90 or whatever they are. i have instructions but they are for a firechief and this is a granny. does anyone know where i can buy parts for a firechief?? thanks for all the help. josh

Originally Posted by ttopmustanggt88

ok so i can go from hot power (black) to one side of switch, then hot black on the other side of switch to the hot black side of blower. and run white directly to blower and that should do it?? what kind of temps do these things normally turn on at?? thanks so much for the info. josh

basically.....yes, that's the way to wire it.

The thermostat switch on my firechief is a honeywell switch.

I took some numbers off of it. L4064A1339 6 0523H 2amps @ 24v AC

If you can figure out what those mean. I'd think most any switch would work, do a search on honeywell limit switches I know they make a ton of different ones, but they mostly do the same thing. Good luck

This is the one I put on the plenum of my furnace. I wired it in series with a t-stat up on the main floor. You can see it is set for the fan to come on at 100 f with a 50f differential. With three 1/4 rounds of ash in the furnace I can hold the house at 72f for about 7 hours when it is 25f out.
Your local wholesale plumbing shop should have it on the shelf.

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 .

Originally Posted by reaperman

The thermostat switch on my firechief is a honeywell switch.

I took some numbers off of it. L4064A1339 6 0523H 2amps @ 24v AC
If you can figure out what those mean. I'd think most any switch would work, do a search on honeywell limit switches I know they make a ton of different ones, but they mostly do the same thing. Good luck

yours runs off a 24 volt transformer.

this is a good point to bring up because this wasn't mentioned before. he should investigate if his thermal switch is rated for 24 volts before doing any wiring.

mga

I'm glad you caught this, I 'm ignorant when it comes to electrical details.

Here are a couple of pics of what mine looks like, the thermostat is on the very top and the conduit is running to the transformer.

bottom picture......

to the right is your 24 volt transformer, and to the left of that is a relay. the relay might turn on the 110 volt blower.

hey....no cover for that stuff? lol

this is what he needs to investigate: whether or not his controls run off low voltage or high. (i'm willing to bet low, but i could also be wrong...lol)