Furnace mounted on its side....
[quote=acefurnacefixer;27853]I think thats common knowllage[/quote
Hopefully to those in the ac/heat trades, but not to a homeowner.
And even that "hopefully" is not always true. I had an ac contractor install a gas furnace horizontally in an attic on a job several years ago. When I went into the attic , the access door was facing up on the unit, thus putting all of the wiring directly above the burner. When I questioned him about this, he became angry and loudly stressed to me that he had been in the business for more than 15 years and this was a furnace rated for either vertical or horizontal applications. I found the installation manuel in the trash pile, and he was right, problem was it could be laid horizontally on either it's right or left side, not on it's back like he had it. I called the distributor and he verified that my interpretation was correct, and finally the installer changed the orientation with much grumbling about how much this was costing him because he was going to have to remake both the supply and return air plenums.