Newbie wood furnace install questions

[rrkroll]

Hi all, thanks in advance for all of your help. Like the title says, I am installing a Daka 521fb and have hit a stumbling point. My initial intent was to install this furnace as an add on. But I have a Horizontal updraft furnace (did not know this until I was reading the manual) Apparently you are not supposed to hook an add on to an updraft furnace. I understand why you wouldn't want to inject heat into the plenum on a vertical updraft, but why wouldn't it work with a horizontal furnace? Also, I keep hearing about backdraft dampers in the furnace Plenum, why would I want a backdraft damper if I am planning on the main furnace fan blowing the heat that the add on supplies? (I know that I need them for the warm air ducts from the wood furnace to the main furnace)
Which brings me to the next question, do I need to use barometric dampers as a backdraft preventer? Or do you generally make one? Where does one purchase these items?
One last question,
If I hook this up with a check (backdraft preventer)in the furnace Plenum and use a larger fan for the woodstove can I effectively run the two in parallel without ruining my updraft furnace? (What I mean by parallel is to just not use the furnace fan, and use only the woodstove fan, basically when the woodstove kicks on, the check in the furnace is pushed shut, and the furnace is eliminated from the heating circuit, and vice versa.)
Sorry for so many questions, just a little perplexed and slightly worried that I just bought a stove I can't use.


Thanks again.

 

[KindredSpiritzz]

not sure i understand your questions fully but i'll take a stab at some. No idea about the vertical/horizontal aspects but my back draft dampers went in the warm air duct between the wood furnace and the gas furnace plenum. The idea being you dont want the gas furnace to kick on and blow air back into the wood furnace. Im not sure how good just using the main furnace fan would work as the hot air needs something to push it from around the wood furnace jacket and out into the duct work. The main furnace fan may just push all that air back into the wood furnace jacket. If back draft dampers are installed then they will be closed and the heat wont get out into the duct work. I sometimes run my furnace fan along with my wood furnace fans but i get enough pressure from the blowers to open the back draft dampers to allow heat to get out into the duct work to be pushed along by the furnace fan. I never installed a barometric damper but mine runs fine without it. Your supposed to have a certain pressure in the chimney and theres something (forget what its called) you can hook up to see if you have the right amount of pressure. If you need a barometric damper you can buy them, they are not very expensive.
Im kind of confused tho, in the first paragraph you talk about using just the main furnace fan to move the air, then in the last you talk about not using the furnace fan and just using the wood blowers.