I know they say not to but why?

Is the air really hot enough to do damage to an air handler that comes from a wood furnace? I know they say it has the potential to over heat since it is basically an uncontrolled heat sorce, if you don't pay attention to it that is. It would just be so convenient to pipe the duct into my return duct and use the air handler to filter and circulate the air using the t-stat on the stove. Thoughts from the experienced would be appreciated. Thanks

The blower motor on your air handler is made to be cooled by the air it pulls thru. If you're feeding it hot air, it isn't cooling like it should. It probably won't fail overnight, but I'm sure you'll see it's life shortened.

Well, it is pulling hot air if I use the heat pump but obviosly not as hot as the furnace puts out. The back up coills are located after the fan so i see what you are saying.

I have seen lots of folks install a large return register in the ceiling over their woodstove. Seems to work well in situations where all of the ductwork is run in conditioned space, versus a cold attic or basement. Not sure it's code or legal, but the air they're drawing is really only a few degrees above room temperature, not enough to be a big factor in the MTTF of the average induction motor.

Do you not have enough room on your supply side duct work?

Yes there is plenty of room on both sides. By supply side do you mean after the air handler? I went ahead and started the install after the air handler. Now I just need to figure out a damper so i am not blowing heated air back thru the air handler. I also want to put a filter box around the blower so I am still filtering the air going thru the system. Keep em coming guys I like the input!

Yes. Exactly.

You need a backflow damper

Question for you: Where will the cold air return on the Englander be pulling from? If this is a basement install you might want to consider running some duct work from the living space to the englander if of coarse code permits you to do so. If it were me I would not want to be pulling cold air from my basement and trying to heat it.

So, if you are not worried about modifying the furnace and effecting your insurance, you could relocate the motor to outside the furnace and jack-shaft or extend the drive through the sheet metal. You would, of course, want to put a ventilated metal box around the motor for safety from fingers, etc. Then you are no longer worried about over-heating the motor.

However, the correct way is to install the wood furnace on the supply side of the existing furnace, as mine is. You lose some points in efficiency when using the non-wood heat source (oil, in my case) as the wood furnace is a thermal mass and loses heat up the stack as draft.

It is in a family room so it is pulling air from living space. I think I will do as others have done and get the universal filter box from USSC. Now I will just need to locate a damper for the back flow.