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Community and Q&A

Wired or wireless thermostat for Mitsubishi single head minisplits

willymo | Posted in Mechanicals on

I’m having a minor disagreement with my Mitsubishi installer (very experienced, Diamond etc.) I have four 6k single heads in four rooms of my house (properly sized, etc.). The installer is insisting on wired thermostats, says the wireless are not reliable. Is there any advantage between the two? Does one have more capabilties than the other? Or do I really need them at all?

TIA, this site has been a godsend for this project!


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  1. Expert Member
    BILL WICHERS | | #1

    While I don’t have any experience with this specific unit, I can tell you that in general yes, wired devices are more reliable than wireless. Wired devices also have the advantage of not needing periodic battery replacements, and remember that batteries like to die around 3am Sunday morning when you don’t have any spares :-)

    I personally always go with wired devices except when I have no other option.


  2. joshdurston | | #2

    I've found the MHK1 to be completely reliable. Temperature control is improved and modulation stability is massively better. I found hear the compressor hunting (it's bolted to the bedroom wall unfortunately), but with the MHK1 it holds a modulation level for long periods of time, rather than changing ever 30sec to a minute, and space stays within 0.5C of set point.

    If you're going to use a wired stat you could just install the remote room sensor (it basically replaces the built in entering air sensor with a wired wall mount) that is cheaper than the full wired stat and allows you to continue using the included IR remote control.

    I avoided Kumho cloud since it is tied to a web service that may or may not be reliable or available especially years in the future. The MHK1 is a local wireless (redlink) interface that will work without apps and the internet, or even wifi.

    1. Expert Member
      BILL WICHERS | | #3

      Sometimes you can quiet things down by mounting the unit on vibration isolators so that it doesn’t resonate the wall. I’ve done this before and it usually makes a pretty big difference at minimal cost. You can get all kinds of vibration isolators from McMaster Carr, among other places, you would just need to figure out which type would work best for your particular installation.


  3. willymo | | #4

    Thanks Bill and Josh. For now the decision will be the MHK1 or just the remote. I don't think I need the cloud.

    This is a house that is sometimes empty during the winter. With oil heat I have often left it at °40-°50 when empty. Is there a way to do this with either the wired, wireless, or remote?

  4. Expert Member
    Akos | | #5

    On a related topic as Mitsubishi's documentation is not the friendliest.

    I have an MXZ with two heads (ducted+wall mount) but would like to treat them as a single zone with a single thermostat. Is there an easy way to do this?

  5. MattJF | | #6

    Akos, does setting at the same temp not work? There can be situations like a large room with two systems, where having them function as one can be better because you otherwise get “crosstalk” between thermostats.

    I don’t know Mitsubishi systems, but if there is a disable input, you could have a relay setup so the master unit disables the slave when it is not heating/cooling. You would still have two thermostats that would need to be set the same. You would have to test if this causes any sort of odd modulation behavior on the slave.

    1. Expert Member
      Akos | | #7

      I'm trying to get away from having two separate remotes. The place is a single story layout, so there is really no need for separate zoning, the only reason for the multi split is the layout is not simple and just couldn't make the ducting work.

      Ideally, it would be a single thermostat that sets both heads to the same temperature set-point and lets each do its own thing. Bonus would be to allow a programmable offset between the zones (ie living space at 75, bedrooms at 72)

      My current thinking is two relay modules wired to a single "standard" thermostat. It just feels like there should be a better way to do this with a multi split.

      1. joshdurston | | #10

        Commercially we slave multiple units together all the time (mostly LG). But other than the hassle of adjusting, it's better to have multiple stats if they serve separate spaces.
        When you have multiple units in a common big space, slaving/grouping is good to prevent fighting.

  6. walta100 | | #8

    You want to avoid the kits that use standard thermostat. They will make your mini run like a conventional furnace. Where the unit runs as fast as possible and then turns off for some time and then back to full blast. The thing that allows minis to be so efficient is the factory controls that allow the unit to speed up and slow down to meet the load and rarely turn off.

    No you do not want one thermostat with a single sensor controlling both units. One of the big advantages of having 2 systems is that you get 2 zones with separate sensor giving you more accurate control in each zone, another advantage of separate systems that sooner or later something will break. If you connect the system together a single fault may take down both systems.

    I am a fan of the wired remote sensor option the minis offers.


  7. Expert Member
    CARL SEVILLE | | #9

    My installation uses Mitsubishi wireless controllers and Honeywell 9000 thermostats on each head. Fairly easy setup and has worked fine for over 2 years. It limits the head to 2 speeds instead of fully variable, but that has not had any negative effect on performance.

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