Proper Coil Placement - Before or After Furnace?

[Taylor]

I have a crawlspace with a horizontal furnace -> coil placement. The coil needs to be replaced, but the tech cannot find any on the market the same size (the coil is an A-type, 20 yrs old).

Current Config: Horizontal Return -> Filter -> Furnace -> 90 degree Bend -> A Coil (Link to Image of Config:

I had one tech come in and say that he can alter the configuration to be horizontal "pull-through".

Return -> Filter -> Flat Coil -> Furnace -> 90 degree bend (Link to Image of New Config:

)

So, my question is: Will this new config cause problems? I've read a couple conflicting statements like:

"The evaporator coil must be installed in the discharge (supply) air of a gas or oil furnace. Do not install an evaporator coil in the return air, or excessive condensation will occur within the furnace."

Then the second image was taken from a site that recommends the new setup for better "thermodynamics" of pulling moisture from the air via a "pull-through" method.

Any help would be appreciated. I've gotten two quotes for fixing my unit:

1. Pull-through - 0
2. Full replacement of furnace + coil (bc they can't fit a coil after furnace) - ,700

Thanks!

[The Daring Dufas]

needs to be replaced, but the tech cannot find any on the market the same size (the coil is an A-type, 20 yrs old).

horizontal "pull-through".

conflicting statements like:

better "thermodynamics" of pulling moisture from the air via a "pull-through" method.

The pull through would be fine if your furnace had a stainless heat chamber like a condensing furnaces but I wouldn't do it on an older steel heat chamber furnace. Price looks kind of high to me. You might try to find someone who can build an adapter. ^_^

TDD

[jamesgangnc]

needs to be replaced, but the tech cannot find any on the market the same size (the coil is an A-type, 20 yrs old).

horizontal "pull-through".

conflicting statements like:

better "thermodynamics" of pulling moisture from the air via a "pull-through" method.

I would not put it ahead of the furnace. A cased horizontal flow A coil is not hard to come by. Worst case you could mix brands. Is the outside unit 20 years old as well?