Ducted Minisplit Temperature Confusion
I have a Midea ducted minisplit system that I really like. But, oftentimes it will not get to the set temp even though it has the capacity to do so. its an 18k btu unit that can pull 1800 watts.
If I set it to say 72 degrees and the current temperature is 80 degrees it will run at high capacity for about thirty minutes and then drop down to using only 500-600 watts even though it is nowhere near the set temperature.
if I hit turbo mode it goes to high capacity for 30 minutes and then drops back to using 500-600 watts , again even if its nowhere near the set temp.
there are two temperature sensors. one at the air handler in the attic, and one at the wall mounted thermostat. I usually have it set to the “follow me” mode, which supposedly uses the temperature at the thermostat.
does anyone have any ideas why this might be occuring?
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Most minis use a sensor in the stream of air entering the unit as its way of determining the rooms temp.
My guess is if you put a thermometer in the return air stream it would read very close to your set point.
If there is a ceiling fan in the room turning it on could help.
Consider looking for the kit to add a wired remote sensor for your model and mount the sensor away from the unit.
Walt
It actually already has a wired remote sensor.
The temperature control on the Midea units is not the same a standard thermostat.
For the unit to modulate it allows the temperature to drift away from the setpoint, this means it generally never reaches the setpoint. The user manual will show how this works. It is not ideal but good enough. I would ignore the absolute value of the setpoint and adjust it until you are comfortable.
I've also had it operate in strange ways when not in auto fan mode, I would try to run it in auto mode and see. You definitely want to run it with follow me mode if the unit is in the attic.
P.S. If I remember correctly, in the installer menu there is an offset you can adjust to get the setpoint closer to reality.
This is the first I'm hearing of the installer menu. I'll have to look for it.
I set it away from follow me more today and it ran at full capacity until it set it back to follow me mode- I think it was using the temperature in the hot attic and it kept running at full power.
I also haven't seen the modulating theory and set point drift in the manual. Maybe im reading the wrong manual lol
Most info you get may be for Split wall mounted HEADS. It is hard to filter this out. Sounds like you have a FULL DUCT system.
I had problems with a fully air handler ducted unit I installed 8 years ago and even the LG service techs I hired to come out back then had not seen installed or seen a full ducted system so did not have a clue. It took years of occasional research to get my temp problems under control.....some obscure setting in wired wall mount thermostat which was not in any manual.
I know my comment does not help but....just trying to point out you have a ducted system.
Your issue might be a little more serious than an adjustment of settings, but I've installed several Mitsubishi concelaed ducted systems and achieving setpoint is a constant struggle. Keep looking for the "installer menu" which is probably called up with a certain keystroke combination on the remote; the Mitsus even use a goofy date-of-manufacture-based PIN that's printed on the back of the remote.
There are various settings that are critical to the proper commissioning of the unit. Techy stuff like static pressure, but also basic comfort settings like how the fan behaves. You'll find a couple settings for dialing in a more accurate relationship between setpoint temp and actual temp.
The default settings are logical choices, but every installation is very different and every user has different excpectations, so I'm amazed that the contractors I've worked with seem mostly unconcerned and unfamiliar with this fine-tuning.
In the end, I've also told people to ignore the numbers and just set it so they feel comfortable. Plus, have to discern what's a control issue and what's an install issue. For example, a duct blowing right across a bed is a major problem that can't be fixed by monkeying in the installer menu. Don't ask me how I know this.