Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit

Mitsubshi Mini Split ?

Been awhile since I posted ! Retired 4 years :)
I am a retired Oil Burner Master in Maine and Ct.
New to the Mini Splits ! I have a Mitsubshi MSN FH12 NA house mounted !
Fired up Oct. 1. Bill for month about 35 $ :)
At 35* + it runs about 2 * higher then set ! I know sensor can be off 2 to 4*f

"Low 30's it runs about 2*f lower ! Does that sound normal ? "

I have a small house, About 800 sq.ft down stairs !
Had to get used to the minor noise when in defrost Joys of a House Mount lol. HB Smith Boiler ( Was with the house :O ) heat set at 2* lower the Mini Split ! Waiting on November bill to see cost !
I am old school Oil so when I hear sounds or something seems off I ask :)
FYI I did not do install,as I no longer have my AC stuff plus I have not worked on one before, and after 40+ years of fixing home owner screw ups I pay a mechanic to do it lol.
Had a guy I used to work with do install as he is in his own business now, Glad I still get trade discounts at supply house's
Thanks for any comments or links about Mini Splits ! I have most of Dan's books but nothing on Mini Splits ! I may be retired but I love knowing how things work ! :)
You all have a Great Thanksgiving



  • SuperJ
    SuperJ Member Posts: 605
    By default mini splits run off the return air temp sensor which can be quite skewed from your space temp at occupied level. The fix is to use a remote sensor/stat. I use the MHK1 wireless stat (looks like a basic honeywell redlink stat).

    With the remote stat, my room temperature stays very close to setpoint all the time, initially I had the same spreads as you and had to constantly adjust it depending on conditions.

    The only downside is the expense, it cost me about $300 for thermostat.
    Richard D._2ratio
  • Richard D._2
    Richard D._2 Member Posts: 151
    SuperJ Thank you for the fast reply ! I will call my supply house's this week to check on that thermostat ! Oil heating I can troubleshoot usually with no issues but this new fangled stuff and me a old fart is past me lol Again Thanks and Happy Thanksgiving