V6-i VRF 50/60Hz       
52     
Midea V6-i Series Service Manual
 
1.2 Modes Set on Main PCB   
1.2.1 Priority mode setting 
Priority mode  can be  set  on  the  outdoor  unit. When  an  indoor  unit  is  in  mode  conflict with  the  outdoor unit  the  unit 
displays  the  mode  conflict  error.  If  the  indoor  unit  has  a  digital  display,  it  will  display  error  code  E0;  if  the  indoor  unit 
display board has LED indicators, the “DEF./FAN” LED will flash rapidly. 
Figure 4-1.2: Indoor unit digital displays and LED indicators 
 
There are five priority mode options: 
1.  Auto priority mode (default): In auto priority mode, the outdoor unit will operate in heating priority mode or cooling 
priority mode according to the outdoor ambient temperature.   
a)  When  the  outdoor  ambient  temperature  is  below  13
o
C,  the  outdoor  units  run  in  heating  priority  mode.  The 
heating priority mode does not change until the outdoor ambient temperature is above 18
o
C. 
b)  When  the  outdoor  ambient  temperature  is  above  18
o
C,  the  outdoor  units  run  in  cooling  priority  mode.  The 
cooling priority mode does not change until the outdoor ambient temperature is below 13
o
C. 
c)  When the outdoor unit restarts under the outdoor ambient between 13
o
C and 18
o
C, the outdoor unit runs the 
same priority as before the last stop. 
d)  When  the  outdoor  unit  is  initial  startup  under  outdoor  ambient  temperature  between  13
o
C  and  18
o
C,  the 
outdoor unit runs in heating priority mode. 
Figure 4-1.3: Auto priority mode control 
 
1.1. Heating priority mode: 
a)  During cooling operation: If an indoor unit requests heating, the outdoor unit stops and then restarts in heating 
mode after 5 minutes. Indoor units requesting heating then start in heating mode and indoor units requesting 
cooling display the mode conflict error. 
b)  During heating operation: If an indoor unit requests cooling, the outdoor unit ignores the request and continues 
to run in heating mode. The indoor unit requesting cooling displays the mode conflict error. If all the indoor units 
requesting heating are later turned off and one or more indoor units are still requesting cooling, the outdoor unit 
restarts in cooling mode after 5 minutes and any indoor units requesting cooling then start in cooling mode. 
1.2. Cooling priority mode: 
a)  During heating operation: If an indoor unit requests cooling, the outdoor unit stops and then restarts in cooling 
mode after 5  minutes. Indoor units requesting cooling then start in cooling mode and indoor units requesting 
heating display the mode conflict error. 
b)  During cooling operation: If an indoor unit requests heating, the outdoor units ignore the request and continue 
to run in cooling mode. The indoor unit requesting heating displays the mode conflict error. If all the indoor units 
requesting cooling are later turned off and one or more indoor units are still requesting heating, the outdoor unit 
restarts in heating mode after 5 minutes and any indoor units requesting heating then start in heating mode. 
Outdoor ambient temperature