Verifying Capacity

[Greg Strump]

I have a 10 year old Ruud air handler model #UBHB-24J11NFGA paired up with 4 year old Carrier condensing unit model #25HBR348A320. I was concerned that the air handler was only 2 tons while the condensing unit was 4 tons. To make matter worse the house is 2629 square feet. Should the air handler be replaced with a larger unit?

[David A. Andersen]

Hell Yes!

You need twice the air flow for the new condenser!

[Doug Edwards]

Curious what size Return Air grill? I find 3 ton and up units with a typical 12 X 24 RA.

[Greg Strump]

There were two returns in different rooms, they were around 16 x 16.

[Dan Bowers, CMI]

Greg -

You don't have the knowledge or experience to make that call. MAYBE they changed the coils inside the case OR ......................

You do have the skill and knowledge to point out the POTENTIAL mismatch and recommend further evaluation by a licensed and competent HVAC contractor.

[Greg Strump]

Good point!

[David A. Andersen]

Crap point.

It makes no never-mind if they changed coils, the AHU can not deliver the air required.

Yes you are qualified to make the call to the mfg with the equipment data and see what gives.

For what it is worth, those filters are too small for the 2 ton.
But I doubt they are 16 x 16.

[Dan Bowers, CMI]

Greg -

As person with degree in HVAC, past HVAC mfg rep, licensed HVAC contractor - I can't count the times somebody left an inside OR outside coil case intact - changed blowers, changed freon line size, changed coils, changed compressors, changed freons, etc ... My 1st post stands pat.

Then think about changes to the house / regardless of SF or filter size (which could be wrong). Orientation of house; insulation levels; the new argon gas windows; etc. WAY too many potentials to name.

Don't screw with it refer it to the people with the experience to properly handle it. Way too many arm chair designers on the web.