Proper selection of an air handler requires answering myriad questions ranging from “what capabilities are required?” to “will it fit?” Only after establishing these basic project constraints can the art of evaluating and selecting an AHU begin.īefore starting this process, it’s important to realize that there will not be a “perfect” selection for any AHU as many competing criteria, not the least being cost, will force compromises. I have a situation where the air handler is 5 ton and the compressor is 3.5 ton (both 2009 models)ĭid you get this off the compressor or the condensing unit?Ī basic definition of an air handling unit (AHU) might be “a box with a fan, coils, and filters.” From there it gets considerably more complicated. They increased the size of the outdoor condenser X3 over a standard 12 seer unit, and had this little compressor wrapped in a blanket could barely see it.īTW Trane also did the same thing monster condensing unit same size coil Carrier was very famous for this when seer rating became a issue. My observation has always been to increase the size of the outdoor condenser on the high seer units. To be honest I have never seen a MFG increase the size of the indoor coil to achieve a higher Seer rating but I am not a mechanical Engineer either. I was taught in two different A/C schools that you never over size the A-coil by more than 1/2 ton.

What was the sweat line on the coil I have a hard time believing that a 3 ton condensing unit can hold enough liquid in its condenser to prevent a 5 ton coil from being starved. Of course you can’t (shouldn’t) go the other way and use a smaller A coil. I had one in my own house until 3 or 4 years ago.Īs I recall the SEER was 12.4 or so then. **We installed a lot of 3 ton condensing units matched with 5 ton A coils **plus a liquid line shut off solenoid valve and an indoor blower time delay relay in those days. They were selling them as a package deal. Back in the late 70’s and early 80’s that’s how Coleman was achieving their high SEER rating.

Ac compressor 3.5 ton 14 seer