GMV5 DC INVERTER VRF UNITS SERVICE MANUAL 
171 
(6) Low voltage protection for the DC bus of the variable-frequency fan's drive board (ODU fault HL) 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  (7) Variable-frequency fan starting failure (ODU fault HJ) 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
The fan's drive board is 
faulty and needs to be 
replaced. 
 
Check if the terminal 
CN503 and CN504 
on the fan's drive 
board are connected. 
Check if the voltage of the 
input power cable is lower 
than 320V 
 
Elevate the voltage to 
380V. 
Check if the terminal CN503 and 
CN504 on the fan's drive board 
are connected. 
Check if the fan's UVW 
cable is connected properly. 
 
Replace the fan's drive 
board to see if the fault is 
solved. 
The fan is faulty and needs 
to be replaced.