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Getting to know Mitsubishi Hyper Heat ...

woobagooba
woobagooba Member Posts: 168
edited November 2022 in Thermostats and Controls
Greetings all. Long time hydronic heat user, first time Mitsubishi H2i user (ducted install). Let the dumb questions begin.

First up, with the thermostat set point lower than the interior temperature and FAN set to AUTO, I still have cool-ish air coming from the ducts. Why? I can disable the air flow by setting the operating MODE to OFF.




Comments

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,882
    edited November 2022
    Gravity? Are the ducts overhead in a cool attic? Cold attic air is heavier than warm air in the home. The cold air will drop into the room as the lighter warm air in the room enters the duct. Depending on the dynamics of the room and the duct configuration, if the warm air us going up thru a central return, and the cooler air is dropping from the supply runs, that gravity flow can get to be somewhat noticeable and uncomfortable, or at least annoying.

    Just one possibility. If your ducts are in the floor then forget you even read this.
    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
  • Hot_water_fan
    Hot_water_fan Member Posts: 1,000
    I have the same one. The blower runs 24/7, so that’s why cool air is blowing. Not great during the fall I suppose.
    EdTheHeaterMan
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,882

    I have the same one. The blower runs 24/7, so that’s why cool air is blowing. Not great during the fall I suppose.

    I wonder if there is something in the programing that can shut off the fan when there is no call for the compressor to heat or cool.

    OR.

    Just shut off the circuit breaker during the OFF Season.
    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
  • Hot_water_fan
    Hot_water_fan Member Posts: 1,000
    Maybe! You could just turn it off on the display during the off season. The off season is just a few weeks here, so it’s not pressing for us and it filters well. 

    I think the blower uses around 80w? 
  • FlyersFan
    FlyersFan Member Posts: 1
    Out of the box Mitsubishi systems run the fan continuously to sense room temperature at the return air sensor. You can change this since you have an MHK2 controller on the wall by going into the function settings in the MHK2. To shut down the blower when the system satisfies you'll need to change IUFC #2 to 3(sensing temperature at the MHK2 instead of the return) and IUFC #25 and #27 to 2.
    woobagooba