Auto Changeover - Mitsubishi Electric BDT CITY MULTI Installation And Pre-Commissioning Booklet

Auto changeover - S, Y, WY Series only
S, Y and WY series units all have the ability to automatically change operating mode from heating to cooling.
There are a number of auto changeover options depending on the system controllers or application.
1. Factory settings
There is no auto changeover available.
The first indoor unit to operate will select the operation mode of the outdoor unit (heating or cooling). The outdoor unit will
remain in this mode until all indoor units are either turned off or have been selected to operate in the opposite mode.
2. Auto changeover - selected from the outdoor unit
This feature will put the indoor unit that has been set to the lowest M-Net address as the master unit. Auto mode will become
available through the wall controller and the outdoor unit will change operation mode (heating or cooling) based on this units'
heating or cooling requirements. All other indoor units will display the same operation mode as this lead unit.
PUHY-P***YHM/YJM set SW4-5 to the "ON" position on the outdoor control board.
PUHY-P***YKB/YLM function 781 set SW6-10 "ON" then SW4-1,3,4,9,10 to "ON" and press and hold SWP1 for 2 sec
LED3 will become lit to indicate the function is now on.
Set SW6-10 back to "OFF".
PUMY-P***(V)YHMB set SW2-5 to the "ON" position on the outdoor control board.
PUMY-P***VKM set SW9-1 to the "ON" position on the outdoor control board.
3. Auto changeover – selected from the central controller with web browser
This is only available on central controllers that have a web browser feature.
Using one of these controllers gives two additional auto changeover control options.
• Weighted average
This looks at the heating and cooling demand of all indoor units within the system at a 15 minute interval. Once the total
demand for the opposite operation mode is greater than 50% the outdoor unit will switch operation mode (heating or
cooling).
• Represented group
This feature allows you to select any group as the master. The lowest addressed unit within the group will decide whether
the system will operate in heating or cooling mode based on the heating or cooling requirements of that unit.
The wall controller will display heat or cool (not auto) but will automatically change when the temperature requirements are
calling for the opposite mode. All other indoor units will display the same operation mode as this lead group.
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