Bosch BMS500-AAU036-1AHCXC - Fan Motor Phase Failure (EC 72)

| 77
Service Manual
Bosch Climate 5000 Series Ductless Air Conditioner / Heat Pump Multi Zone Outdoor Units (01.2023)
8.6.15 Lack phase failure of outdoor DC fan motor (EC 72)
Troubleshooting:
Figure 81
Checkthe fanthree-phase
output for obvious open
circuit
Poweroff,then restart theunit
2minutes later.Is it still
displaying theerror code
Theunit operates
normally
Checkthe wiring of fan
motor.Areall theconnections
good?
Correct theconnections
Checkwhetherthe three-
phaseresistanceof thefan is
symmetrical
Replacethe fanmotor
Yes
Yes
Yes
No
No
No
Replacethe main PCB
No
Problem is solved
Yes