Is It Safe If I Just Run Half Of My Minisplits? - Ask The Expert Episode 315

Today's question is,

"Hey Dan. Is it safe to only have one air handler running on a ductless minisplit multizone, and the other one turned off? Or do they both have to be running at the same time? I have a 36k multizone condenser, and two 12k air handlers connected to it."

Yeah, that's fine.

As long as they are both connected, and you aren't running it with less than 50% of capacity, you don't have to run both units at the same time.

That's perfectly fine. No problem at all.

10 comments (view/add)
  • Allan Rivera
    Allan Rivera
    Posted on 9/20/2022

    I have a 36k multizone with 4 zones. three 9k and one 12k. I have only the 12k running and all 9k's are off, one of my 9k is making a noise and gets cold. is that normal? but when i turn that 9k on it works normal.

  • Rebekah Muller
    Rebekah Muller from Ingrams
    Posted on 9/22/2022

    You need at least 1/2 capacity of the condenser in air handlers to be operating for the system to function normally. This means that you would need to turn on another air handler for your system to work properly.

  • Brian
    Posted on 8/11/2022

    Will the condenser electrical load be reduced when you only use 50% of the capacity

  • Rebekah Muller
    Rebekah Muller from Ingrams
    Posted on 8/18/2022

    While you'll save on not running additional air handlers, the condenser will still use full electrical capacity.

  • Mike B.
    Mike B.
    Posted on 8/9/2022

    Can I run a 2 zone system with only one zone connected? The second zone space is not yet constructed (over garage expansion). To be completed after Summer heat .

  • Rebekah Muller
    Rebekah Muller from Ingrams
    Posted on 8/11/2022

    It's fine if the operating air handler is at least 50% of the BTU capacity of the condenser.

  • Peter Sachs
    Peter Sachs
    Posted on 7/20/2022

    So if on my second level, I have three bedrooms, two with 6k units and one with a 9k unit all running off the same ext 24k condenser and if the person in a room with one of the 6k units is more finicky and often is the sole user of heating then I should consider a different setup?

  • Rebekah Muller
    Rebekah Muller from Ingrams
    Posted on 8/18/2022

    Potentially. Especially because most mini-splits won't be able to heat and cool with different air handlers at the same time. Even if you are heating at the same time, it would likely be best if the "finicky" user had their own system, so that it does not put undue stress on the entire system if the other zones aren't on.

  • James
    Posted on 7/12/2022

    I didn’t know that was ever a concern. I waiting on delivery of a 21k (12/9) and a 27k (18/9) the 9s are going in 2nd floor rooms that will be used infrequently. Should I be okay using the 12 and 18 primary? I know that number is more that 50% of the total. Does that mean it’s running over 50% capacity ?

  • Rebekah Muller
    Rebekah Muller from Ingrams
    Posted on 7/15/2022

    That will be perfectly fine. As long as the operating mini-split is equal to or more than 50% capacity of the condenser, it should function well.

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