Gree GMV-450WM/B-X - Page 171

GMV5 DC INVERTER VRF UNITS SERVICE MANUAL
168
13. Analyzing of faults in the variable-frequency fan drive's control system
(1) Communication failure between the fan's drive board and control board (outdoor fault C3)
(2) Faults in the IPM temperature sensor of the fan's drive board (ODU fault H7), current detection circuit
(ODU fault HC) and out-of-step protection (ODU fault H9)
H7, H9 or HC
Check if the fault is solved
after turning on the system
for three times
The fan's drive board is
faulty and needs to be
replaced.
Complete
No
C3
Check if the control board and fan's
drive board are power on.
Check if the fan's drive board and
compressor's drive board are well connected
to each other using the communication cable.
Check if the dial switch of
the fan's drive board is
correct.
The fan's drive board is
faulty and needs to be
replaced.
Complete
Yes
Replace the control board if its LED is off;
replace the drive board if its LED is off.
If not, reconnect them. If the cable is not
conducting, replace the cable.
Switch the dial switch of the drive board to 00 in
a signal-fan system. For a double-fan system,
switch one to 00 and the other one to 01.
Yes
Yes
No
No
No