Counterflow A/C

Paul Fredricks_3

Does anyone have any suggetions for installing A/C in a counterflow oil furnace? There would be room to put the coil in the return, though I can't imagine that would be very good for the heat exchanger.

Empire_2

Paul

There is nothing wrong with that. A Lot of carrier Roof top units have the same draw,..over the evap first then past the heat exchanger. If it is easier for you, then that's where it should go.

Mike T.

Paul Fredricks_3

Oh... yeah... I knew that. I've only worked on a thousand rooftops. Thanks for hitting me in the head with a 2 x 4 and waking me up.

Empire_2

Your welcome

I try to at least smack 1 person a day and get hit myself a couple of times a week. Things that make ya go huhhhhhhh.

Mike T. ;-)

John Mills_5

Trashed heat exchanger

and those same Carrier (and others) rooftop units with coil before the heat exchangers are a ball of rust. In 14 years of our selling Rheem furnaces with tubular heat exchangers, not 1 has failed. We sold a 3 ton gas pack, that poor tubular was shot in 6 years, full of holes. That's what happens when cold air blows on a heat exchanger. Not sure if a heavier oil exchanger will hold up better but I'd bet the mfr would say don't do it.

Kniggit

not just exchangers

but what about that poor steel blower wheel? and the motor? basically anything in that furnace not plasic will attract condensation and rust, its only a matter of time.

Empire_2

Cod air on heat exchanger???

That's news to me. I guess we would have to eliminate economizer actuators to so that puppy wouldn't rust out. I couldn't disagree with you more.

Mike T. No diss. intended.

Paul Fredricks_3

The other thing I was thinking about was the flow of air. We would have to use an A-Coil. The air would have to flow through backwards. I would think the velocity would increase going through due to the decreasing area at the drain pan. I'd think that would knock water off the coil and into the blower area. A roof top usually has a flat, upright coil so there would be less chance of that happening.

Our sales guy decided to quote an attic unit instead. Doesn't want to risk possible problems down the road. Still, does that mean you can't have A/C with a downflow furnace?

Kniggit

not exactly

With a gas or electric they place the a-coil under the furnace, but any time an a-coil is downstream of an Oil furnace no plastic drain pans alowed.