Midea V8 VRF Series Service Manual page 49

V8 VRF Indoor Units
6.1.7 A74 - The error of the AHU Kit slave unit is sent to the master unit
Note: When multiple AHU Kits are connected in parallel, the master AHU Kit (referred to as the master) communicates with the
ODU, and the slave AHU Kit (referred to as the slave) communicates with the master control box. When the slave fails, the slave
sends a fault signal to the master, and the master displays the slave fault "A74".
Error display
Master unit and slave unit: stop. Other IDUs of the same system: operate normally.
Error impact
ODU of the same system: operate normally.
Error trigger The error of the slave unit is sent to the master unit
Error recovery Automatic recovery

Possible cause

Troubleshooting
Note:
1. The error code can be queried after the slave is connected to the display box (during field
service, the display box can be temporarily removed from the master unit and connected to the
slave unit)
48
Digital display
The slave unit is faulty.
The master unit's main control board is damaged.
A74
Check the running status of
the slave unit, confirm and
resolve the error (1)
Error
in slave unit
After troubleshooting, is the
master unit error code
cleared?
Yes
Fault cleared
Display position (master)
Display box and wired controller
No
Replace the the main control
board of the master IDU