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Buster Foster
04-23-2007, 06:39 AM
I inspected a split-level condo this weekend and it had an AC arrangement I have never seen before.
There was a HVAC suspended in the crawl space and another HVAC unit in the ceiling of the upstairs landing. The problem is there was only one 2.5 ton compressor outside. From inside the crawl space I found where they had put a T in the refrigerant lines to supply both units.
Is this acceptable? I was not able to find data plates on either of the inside units to tell me coil tonnage. In the end I just told them I had never seen this before and that I felt it should be evaluated from top to bottom. It did have some other issues that neede to be addressed.
Does anyone know about this type of set-up?
Thanks,

Brian E Kelly
04-23-2007, 09:06 AM
Depending on what the manufacturer it is? Most standard A/C system you are not allowed to split into a line set as the freon will take the easiest way and one air handler may not get enough and will freeze up. There are several manufacturers that make what is called a mini split with two to four indoor air handler and one condensing unit but with these they all have a seperate line set for each indoor unit.
Most likely the split into the line set was a joe homeowner's handi work.

Jim Price
06-13-2010, 07:14 PM
Buster:

Manifolded or "bullheaded" evaporator sections present quite a few challenges. Theese include (to name a few) proper superheat control, oil return, and capacity control issues. Usually the only time i have seen this type of system operate are in situations where a 2 evap circuit Is applied to units in a twinned configuration, where the units will likely have similar airflows, similar latent and sensible loads etc. If I were you I would check (with model and serial number) with your distributors service management to see if that unit has multi-evap capability. That being said, I would say that this is a common application for many of the variable capacity duct free spilt systems offered by many manufacturers. It is FAR less common in a traditional Air Handler / Condenser application.