Newby Question about placement of heat Exchanger?

[Fordracing302]

Hi Guys

New to the site and learning alot,I am in the procces of buying a Bosch/MESys boiler with a Janfire nh pellet burner,What I want to do is install the boiler in my detached garage with a unit heater,then run pex to my house and hook up a indirect water tank,and then put a heat exchanger in my oil burning downflow furnace and use its fan for supply,I have done alot of searches and I cant find out where do you place the heat exchanger,do I have to move the furnace and install it in the duct work under the furnace? or in the furnace under the fire box,or underneath the fan on the top.

Thanks in advance

Thanks Steve

 

[Medman]

I also have a downflow furnace, and I have installed the heat exchanger at the bottom of the furnace in the start of the supply ducting to the house. This meant raising the furnace up about four inches. I have an electric furnace which will still power the elements if the hx is cold.