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Mitsubishi MZ -FH12nah

smokey059 | Posted in General Questions on

Does anyone have a link that would show the btu output of these mini splits at  the -13 rating there designed to operate at? I have a small room (550sf) that I want to heat using one of these.   I used a mini split sizing program to get an idea of how many btus it would take to heat that area and it said 8500 btu. 
There’s only one Mitsubishi installer in my area and I’d like to be somewhat educated on the output at cold tempatures(99% temp here is -16) so I don’t get an over or undersized unit. 
Yes I know he should do a heat load calculation but my experience with these hvac contractors around here is  they always just use some square ft figure to arrive at a heat load calculation while their telling you theyve been doing it that way for 30yrs. 
So if I have an idea of  the rated output at low Temps of the Mitsubishi m series hyper heat units i could tell if the contractor is way off on his recommendation. Thanks

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  1. silkwj | | #1

    Normally it'd be here:

    But this particular unit is a bit lacking in documentation posted. However, the main M-Series Engineering Manual, here:\M-Series_Engineering_Manual.pdf, page 236, I think is what you're looking for. Double check the model number.

    basically, 100% down to 5F, sloping down to about 73% (of rated) at -13F.

    There's also lineset length losses to consider but it's not nearly as much of a derate as the outdoor temp.

  2. Expert Member
    Akos | | #2

    Not sure if this comes with a pan heater, but in your colder climates, it is a must for heating.

    You can probably go down to the FH09 but there isn't much difference in performance at low load.

    1. Expert Member
      Dana Dorsett | | #4

      >"Not sure if this comes with a pan heater, but in your colder climates, it is a must for heating."

      It absolutely does have a pan heater.

      The "H" in the "...NAH" indicates it's shipped with a pan heater. The "...NA" ( no "...H") version has no heater when shipped, but the heater part (model MAC-642BH-U ) can be added later if desired. The controls for the pan heater are already on board. The control algorithm for the heater control can be found near the bottom of the left column of the NEEP listings.!/product/25895!/product/26102

      Note- the NEEP listings screwed up which version comes with the heater already installed vs. the one that can be upgraded with the heater kit.

  3. smokey059 | | #3

    Thanks for the info. That should at least give me enough to know if the contractor is close. He's suppose to show up today so well see. I appreciate the help

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