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Community and Q&A

Mini Split 3 zone

c3k | Posted in General Questions on

I want to put a 3 zone mini split unit in the upper story of my house.
My plan is to run the AC lines through existing duct work to each room, mounting the indoor unit where the old vents were. The vents are mounted on wall above doors so the only thing I would have to figure out is the water drains for each indoor unit. I plan on putting small tanks with pumps draining to an existing drain line in attic. My main concern is would the insulated line runs have a drip hazard running inside the old fiber ducting? Does this design seem sensible? The outdoor unit would mount outside the wall where current indoor Furnace is located and free up a closet space at the same time.  Thanks for any advise.

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  1. Expert Member
    Dana Dorsett | | #1

    Unless it's a very large upper story, even the smallest 3-zone multi-splits are likely to be sub-optimally oversized for their loads. It may be more reasonable to install a right-sized ducted mini-split, utilizing the existing ducts as DUCTs rather than a refrigerant line chases.

    Run a room by room Manual-J cooling & heating load calculation before making any purchase decisions.

  2. colinsmith | | #2

    A downside is removing the possibility of ever using the existing ducted system as a backup or auxiliary system. This may not be important to you.

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