Any issues with using a smaller A-coil?

11 years ago

I'm in the process of getting everything to
switch from an AC unit to a Heat pump for dual fuel.... My problem is
the A-coil..

My current setup is a 3.5 ton AC,a York gas furnace (100K BTUs), with an ADP coil rated at 3.5-4 tons.

Now because I don't know anyone that's a carrier dealer .. Carrier
distributor has the ADP coil I want for the heat pump, that's a direct
replacement for my existing coil but I can't get this coil. My local
supply house doesn't carry any left hand coil or ADP's aluminum coils. Because of this, I'm
thinking about just getting a Goodman coil rated at 3-3.5 tons, because I
know it'll fit in my existing case..

So what are possible issues with going with a smaller coil? Might it
actually be more efficient, since the HP will only be 3.5 tons, or should I
keep looking for a direct replacement (4 ton coil), since I'm good with
the performance of what I already have?

Thanks!

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Comments (5)

klem1
11 years ago
Coil capacity needs to match heat pump. If it doesn't fit up to duct,it's simple to adapt.
dovetonsils
11 years ago
What is the brand of heat pump you are getting? It is even more important in a heat pump than an A/C to get a matching indoor coil (according to the AHRI directory).
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crab_dae
Original Author
11 years ago
I'm looking to get the Rheem/Ruud RP1442AJ1. When I checked the AHRI directory, they have it matched to a 4TON coil. But I'm not sure if it will matter because the furnace blower is only capable of 1200 CFM and AHRI matches are all 1300+ CFM..
mike_home
11 years ago
You need to match the coil with the condenser. It is very common to use a coil that is larger than the condenser as long as it a legal match. I have this situation in my house. The air flow is determined by the size of the condenser and not the coil.

If the new coil is wider than furnace then a transition piece can be fabricated between the two. I also have this in my house.
crab_dae
Original Author
11 years ago
Thanks folks... it seems a larger coils can't hurt... even help with the dehumidication ... but a smaller coil could might cause problems. . My coil search continues again...