Getting ready for the Bio-Mizer

[Jeff]

I'm in the process of determining everything I need to get, and everything I need to know in preparation for the delivery of the Bio-Mizer.  My installation is pretty straight forward. The heat exchanger will be mounted over the down draft duct on my furnace, using the furnace fan to distribute the heat.

My problem is, I don't know how to activate the furnace fan aside from running the furnace.  I'm pretty sure it should be a matter of connecting another thermostat to it as I think the furnace is new enough that it is set up to be used in a central air system as well.

  I have a couple photos of the wiring on the furnace, and I think the one photo shows where the wires from the thermostat hook now. I only have two wires coming from the thermostat. I'm thinking that there is a place to hook up an additional thermostat on those empty connections. If thats the case, wouldn't the fan also kick on simply by jumping the correct two connections?  I'm scared if I just try to jump something, I might fry something.

Can anyone make heads or tails of the pictures? The link is to a large photo of the wiring schematic printed on the access door.

https://forestryforum.com/biomizer/furnace_wiring.jpg

[Bro. Noble]

Jeff,  we have a dual heating system that is probably similar to what you are doing.  We have electric heat and an outside wood furnace.   The same thermostat works everything including the AC.  There is a sensor on the hot water line from the boiler that is connected to a microswitch that shuts off the electric unit when the water gets above somewhere around 110 degrees.  If the fire goes out,  the electric heat comes on.

[ronwood]

Jeff,

Would you be willing to use a second thermostat. If so I wil try and find my diagram from Central Boiler to shows you how to wire the thermostats so that you don't have to get into your wiring.

Ron

[ronwood]

Jeff,

Diagram that I put together for my brother's electric furnace when he added a outside furnace. Note that this diagram is for 230 Volts. You probably will only have 110 Volts  if it is a gas furnace. I think this would be the preferred method over the one that I mention in the previous post.

Ron

[Jeff]

Actually, I  do want to, and prefer to use a second thermostat.

I'm wondering if someone can tell by my diagram and photos where to hook the wires on mine...

[ronwood]

Jeff,

If you use the diagram from my second post I would attached the NO lead of contractor to the RD (red)  wire going to the motor which will run the fan motor at low speed. Fan motor is the one that is referenced by not 1 in your attached drawing.

Ron

[beenthere]

Jeff
To me, the red and white wires look to be coming from the thermostat. When that thermostat calls for heat, it simply closes a switch (same as adding a jumper between the two posts).

If you want a second thermostat to do the same as the existing one (when that connection is closed), then simply add it's wires to the red and white shown.

If my assumptions are true. It is low voltage (that you can check with a meter) going out to the thermostat.

[Jeff]

Kent, that wont work, as that will kick the whole furnace on. I only want the fan to come on.  I'm thinking that there is an AC side to this, where the fan kicks on when a thermostat rises to a certain temperature, the fan kicks on as well.  Seems like I could use that system, by reversing the thermostat.

[beenthere]

You are right Jeff. I missed that "Just the fan...."

You can get a thermostat that switches on 110 power...that could be wired to the fan. Just make sure the 110 supply is the same side (leg in the service box) as the furnace uses to power the fan.

[thecfarm]

Wish I could help you.I have mine outdoor furnace hooked up just the way you are trying to do,thermostat and all.I don't remember about the AC side being mentioned.I can still use my oil furnace if I wanted too.The blower from the oil furnace forces air through the heat exchanger.You can come see how mine is wired up if you want.  :D  If I did not have a bunch of wood I would of looked at the Bio-Mizer alot closer.I saw them at the 25th Ann show.I know of one sawmill I can get a pick up load of sawdust for $7.Probaly with a little bit of seaching I could find 2-3 more selling sawdust.

[ronwood]

Jeff,

In the diagram that I attached to my previous post the contractor show is not in the your system.  Your new thermostat will only use the heat cycle.

Ron

[ronwood]

jeff,

Uploaded another diagram. It is attached to my 1st post.

Ron

[Jeff]

Hey Ron, that looks like exactly what I need to do.  Looks like the g terminal on th furnace will get one wire and the R terminal will get a second wire if I am looking at this right

[Furby]

G and R should do it, you can place a jumper as Beenthere suggested as it's only 24v.
Screw the jumper into G and hold it to R to see what happens.
Any kind of switch can be placed in line, don't even need to be a thermostat, I used a wire nut for a few months before. :

[Jeff]

I'll go give it a try...

[Jeff]

That was it fellers!  THANKS!

[Reddog]

Messing with your furnace just before the coldest days this year?   ;) I can just hear Tammy if you short out the board.  :D

[Jeff]

Honestly, we dont hardly use the furnace.  We heat the house with the Gas Fireplace. Its just as efficient and a lot more relaxing. It keeps the living room cozy, theoffice and kitchen comfortable, with the bedrooms on the cool side. Just the way I like them for sleeping.

[Jeff]

The Bio-Mizer thermostat is installed and functioning.    I went down to the do-it center this morning looking for a cheap thermostat.  They had about 10 different ones with the only one being less then 20 bucks looked like it might break taking it out of the package. So, I gave up and started to leave. Walked arounf the end cap of an Isle, and there was a digital programmable thermostat normally marked at $41.49 for $19.99.  SOLD!  I then walked around to where the thermostat wire was. Not knowing how much I would need exactly, I realed off about 3 wing spans. About 16 to 18 feet I guessed at .22¢ a foot.  I took the wire up to Bill at the counter and said, bill how much wire have I got here. He didnt even look at it, he looked me back in the eye and said  8 FEET.  I started to say something and he said louder "8 FEET"    I said, O.K. Bill ;)

Any how, been a long time since something went that well. :D   Even installing. As you can see in the photo, that is the furnace closet door. The furnace is just on the other side of the wall from the new thermostat. 

[farmerdoug]

Jeff,

Now that you have your fan problem solved and thermostat installed, how are you coming on the heat exchanger?

Bio-Tam asked me if I had everything ready for the Biomizer.  I told her that I have only to hook up the lines and power to the CB so I am ready. ;D 8)

[Jeff]

I'll be going to Central Boiler Monday.  Rather then Tammy going back to work by herself, I'll go with her as central Boiler is just on the other side of town from where she drives.  I'm sure I'll be done way before she is done driving, but I can take a nap in da truck.

I wonder if they will sell that pre-insulated pex stuff other then by 100ft.  I only need less then 50. Maybe 30. I'll be measuring for sure tomorrow.

[thecfarm]

Just so you know,if you don't all ready,when my out door furnace was put in I told them the lenght and than they added on 10 feet.Just to make sure all of the bends and everything else is included.They than put it inside black drainage pipe to protect it too.They told me to put in expand foam into the black pipe to keep out the cold air where in went into the ground and where it came through the cellar wall.

[Jeff]

One more step closer to being ready for the Bio-Mizer.  We have the pad ready for it to sit on. Its made up of 33- 4"solid 8x16 cement blocks.  I scraped the snow down to the frozen ground, then Tammy and I drug them around 5 at a time in that poly sled.  The snow was so deep and fluffy, that it was not any fun at all. I figured one trip and the snow would pack and get slippery. No such luck. Its to cold. Just a bunch of deep powder.  Anyhow, this step is completed.

I was going to pick up all the other installation parts today, but that was put off until tomorrow.

[farmerdoug]

Looks good, Jeff.  8) I thought your son was going to help?  But I guess Tammy worked in a pinch. ;) :D :D

[Jeff]

As usual, he became unavailable. :-\  I'd rather work with Tammy anyhow. She's a lot tougher.