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Smaller multi head mini split system using branch box

Trying to find out if there is a lower Btu (1.5-2 ton) mini split system that uses a branch box. I have a new addition highly insulated that could use a 3 head system. But since the walls are reinforced concrete (ICF) it will be difficult to run 3 refrigerant lines to the exterior. All of the systems I've seen that use a branch box are in the 48k Btu range. Does such a beast exist?


  • JUGHNEJUGHNE Member Posts: 6,913
    Is there a basement under the rooms?
  • ratioratio Member Posts: 2,438
    IDK about the smallest sizes available, but some of the multi head unit I've seen are connected via tees &| manifolds, & not home runs to the outdoor unit. I'm unaware of a small hear recovery unit, that is, a small system that uses a branch selector box.
  • CookhigheffhausCookhigheffhaus Member Posts: 5
    Yes there is a basement. But the ICF goes to the footings so for a 3 head system I'd still need a hole large enough for 3 lines. The basement walls are 8" reinforced concrete -- 1st and 2nd floors are 6"
  • EBEBRATT-EdEBEBRATT-Ed Member Posts: 7,050
    Concrete can be easily drilled by someone with the right equipment
  • JUGHNEJUGHNE Member Posts: 6,913
    If the inside walls are not covered you could bring 3 line sets thru the basement wall and up the inside wall.
    The inside units work pretty well on an inside wall.
    The drains could come down inside the wall also.
    No exposed line sets at all, just entering the basement wall.
  • CookhigheffhausCookhigheffhaus Member Posts: 5
    Just for grins what size hole would I need for 3 linesets for mini split? Two head units would be 7000Btu and one 9000.
  • Ron Jr._3Ron Jr._3 Member Posts: 595
    Typically , one 7k or 9k unit uses a 2-1/2 inch hole. If you wanted to run all 3 units through one hole I'd think 5 or 6 inch.
  • JUGHNEJUGHNE Member Posts: 6,913
    The smaller units typically have a 3/8 and 1/4 OD line, both insulated. I use a 2" PVC conduit sleeve which is a strong 2" inside for the copper lines, power cord and drain.

    If the drains terminated inside the basement then you have less passing to the outside.
    A 3" PVC sleeve might work without the drain included.
    If you have to hire or rent a core drill, the number of holes may not cost much more. The size might.
  • IronmanIronman Member Posts: 5,626
    Mitsubisi Hyper Heat would use branch boxes, but the additional cost of the equipment and branch boxes would far outweigh the cost of core drilling a couple of more holes. Unless you want a system that gives full heat output down to 5* outside.
    Bob Boan

    You can choose to do what you want, but you cannot choose the consequences.
  • pecmsgpecmsg Member Posts: 1,427
    Highly insulated concrete you may only need a very small unit. Look at there Ducted unit.
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