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Mitsu ducted mini MRCH1 installer setting questions – GreenBuildingAdvisor
- August 16, 2025
- Posted by: wendy
- Category: Uncategorized
Per Allison Bailes article about mini splits, running the fan 24/7 increases humidity.
Is this the case for ducted minisplits? My SEZ indoor unit fans run 24/7 as set up by the installer. I thought this is because the exterior unit is inverter driven and thus always has some refrigerant going through the coils, so the indoor fans would always be on?
The MRCH1 controller kit installation manual includes an installer setup table detailing the functions. Mitsu Application Note 3048 indicates if function 127 = 2 (stop) the indoor fan unit will turn off when cooling setpoint is met. Is this the setting I want to follow Allison Bailes advice?
I’d also like to understand some of the other settings.
1. My MRCH1 has a few different functions than those listed in the Installer Setup Table. Example, 111 and 117 are not options on mine, but mine has 116, which is not listed on the table. Is there some sort of firmware update I need or are there different versions of the setup table?
2. 105 (Auto Energy Savings) is not an option on my MRCH1. It skips from 104 to 107
3. 110 (High Performance Filter installed) is set to 1 (no) on mine. I use 1″ MERV 13 filters. Should I change this setting to 2 (yes)?
4. 146 (Drying Mode) is set to 0 (off) on mine. If I set it to 1 (on) will my MRCH1’s show a dry mode that I can use in the shoulder season to dehumidify?