Corn Burner Linked to Furnace's Cold Air Return

You could switch the fan on when you need to circulate the heat. There is a switch on most thermostats, for the fan, that says "ON" or "AUTO". Switch it to "ON" to run continuously. Otherwise you could wire a second thermostat for the corn burner with an "A/B" switch to the blower motor for the two thermostats.

You could also get high tech and build ( or possibly buy ) an electronic switcher.

I don't know if a dual thermostat is made for two different units, I am sure that someone has thought of it, but if not maybe I'll invent it and you can be my first customer. If it is made then all you need to do is buy one and install it. Best of luck.

I made up a "reverse" thermostat by buying a cheap one and making it so it would turn on when the heat got up to a certain temperature and shut off when cool....kind of like an air conditioning theromostat. I have it in a room with a pellet stove, and when the pellet stove gets the room up to whatever it's set to, the house fan turns on and sucks the heat to the other end of the house where the return is. I have also made a small relay box for this thermostat that turns the fan on and off via the power already going to the fan. I power the relay and thermostat with a radio shack 110v to 5 or 6v transformer. The house's furnace is an LP with a forced hot-air system. (In the summer the pellet stove-room t-stat also allows us to run the fan and circulate the individual a/c units air around the house.

I believe there is a thermostatic switch in the corn burner already that activates the blower. I want to hook the lp furnace fan up to that switch so it turns on with the corn burner blower. I guess I just need to know what wires to connect to make this happen.

Vince : I just reviewed your blog and suggest you give me a call or at least give me the name of your stove ... we manufacture corn stoves here AND HAVE BEEN DOING SO FOR 19 YEARS ... WE ARE FAMILIAR WITH WHAT YOU ARE TRYING TO DO ...CEEG

Assuming your corn burner has a thermostat. If the voltage of it's thermostat is the same as the thermostat in your furnace (12V??) you should be able to wire it in the same as your existing furnace thermostat.

However, a lot more information is needed to properly answer the question.

I have a similar situation. I use my existing furnace as a back-up.

My system is wired to the fan switch in the furnace. I have installed a second wall thermostat that controls the fan requirements and the heat source. It's a dual 110V thermostat for an electric baseboard system. One side turns on the heat pump (110V) and the other side turns on the fan (12V).

The nice part about the dual thermostat is that I can adjust one side (heat pump) to come on a bit sooner than the other with the calibration screws. For me the heat source is hot water and it allows the pump to come on a little sooner than the fan and get the heat exchanger up to temperature before blowing.

Install a thermostat on the wall near your corn stove. Run thermo stat wires to your furnace hooking up it up to switch on off the fan with the AC setting off the thermostat. You could even use the switch leg from the thermostat to the AC compressor contactor. To an another contactor to provide power to in line duct blower at your hook up on your stove.

If it is an "add-on" furnace, connected to a common hot air plenum, and both furnaces have thermostatically activated blowers, the two furnaces will "talk to each other", that is, one will heat the other and eventually turn on its blower automatically when it heats up to the turn-on point. My oil furnace triggers the wood furnace blowers (which have a more sensitive thermostatic switch) that way. I don't have the wood hooked up to the cold air returns, tho. They just go to the main (oil) furnace and the wood furnace blowers get their air from the ambient cellar. If you want the blower for the main furnace to come on without firing the furnace, and before the other furnace heats it to the trigger point, then you can manually turn it on as another post says, or set the "on" point for the main furnace blower so it will come on at a lower temperature.

vince1028; contact your heating wholesaler for a 24 volt current sensor, it has a metal clamp that senses when the pellet fan starts up. wire the 2 wires to your main furnace terminals R & G, R is 24 volts & G is the fan/blower relay. Aprilaire sells one, no need to cut any power wires perry