Help with size of unit - InspectionNews

neal lewis · #1 (**permalink**) 07-31-2007, 04:50 PM

Can anyone hazard a guess at the size of this Rheem/Ruud A/C air handler unit with model number UBHC-17AOONFA. I would guess 1.5 tons, but I need more than a guess.

Brian E Kelly · #2 (**permalink**) 07-31-2007, 05:41 PM

Yes that is a 1 1/2 ton unit

neal lewis · #3 (**permalink**) 07-31-2007, 05:48 PM

Brian, I did manage to find out the size. The 17 in the model # is just the width of the air handler cabinet. The 1/4 horsepower rating on the label puts it at 2 1/2 or 3 ton.

Brian E Kelly · #4 (**permalink**) 07-31-2007, 05:57 PM

Okay but I have never heard of the size of the air handler in the model # before. Is the coil; mounted in the air handler or on top of the air handler? And what is the model number for the outdoor unit? That will tell better of the size along with the model # of the ref. indoor coil.

Jerry Peck · #5 (**permalink**) 07-31-2007, 06:33 PM

With Rheem and Rudd, there will be two model numbers and two serial numbers.

The main one on the cabinet is for the air handler itself - ONLY.

For older units, remove the cover to look at the coil (like you do anyway, right) and you will see the coil model number and serial number on the coil itself.

For newer units, the coil model number and serial number are on the cover to the coil.

ONLY the coil model number gives the size, not the cabinet model number.

I found this out by scratching my head and trying to figure out 'what to heck is going on here with these model numbers', when I looked at the coil (back on the older units when I first started out) I noticed another nameplate there with different model and serial numbers - why don't the model and serial numbers match??, then noticed that the coil size was that model number.

neal lewis · #6 (**permalink**) 07-31-2007, 08:22 PM

[quote=Jerry Peck;13926]
ONLY the coil model number gives the size, not the cabinet model number.
QUOTE]

You are correct, sir.

The Rheem site says that the A in the cabinet model # means that the coil was not factory installed. This was newer, but i guess I didn't see the separate coil model #. The 1/4 HP gives me a good enough idea; I was thinking it was 1.5 tons at first.

Brian, the condenser was an older ICP brand.

Jerry Peck · #7 (**permalink**) 07-31-2007, 09:38 PM

Quote:

Originally Posted by neal lewis

The 1/4 HP gives me a good enough idea;

You've lost me there Neal.

What, and why, does the 1/4 hp suggest anything to you?

That, to me, would be the rating of the fan motor, which could very well be a variable speed or multi-speed fan, with the speed varied for the different tonnage coils simply by unplugging the black wire and plugging on the red wire, or the yellow wire, or the brown wire ...

Educate me on that 1/4 hp relationship to size.

neal lewis · #8 (**permalink**) 08-01-2007, 11:31 AM

Link to Rheem air handler installation manual page 3 has info on motor size relating to air handler capacity. As I see it, the 30, 36 is teling me 2 1/2 or 3 tons. Best I can figure.

http://216.122.22.11/FetchDocument.a...e-b28e273cfed6

Jerry Peck · #9 (**permalink**) 08-01-2007, 03:22 PM

Quote:

Originally Posted by neal lewis

Link to Rheem air handler installation manual page 3 has info on motor size relating to air handler capacity. As I see it, the 30, 36 is teling me 2 1/2 or 3 tons. Best I can figure.

I see what you are saying, sort of.

It does seem that they are using 1/4 hp fan air handler units *for* 2-1/2 and 3 ton condenser units. It's not saying that's the size of the air handler unit, though.

What size was the outdoor condenser unit?

neal lewis · #10 (**permalink**) 08-01-2007, 03:35 PM

3 tons, and the system lowered the air temp in the vacant house about 1 degree after running for 2.5 hours. Way undersized is my best guess.