Gree GMV6 DC Inverter VRF Units Service Manual
2.86 "H9" Loss of Synchronization Protection for Inverter Fan
Fault display: main board of outdoor unit displays
Fault diagnosis:
If the fault code displayed on the 2-digit digital LED of the outdoor unit's main control board is H9, it
indicates the loss of synchronization protection for the inverter fan.
Possible causes:
■ Poor contact of fan's UVW cables;
■ The fan is damaged;
■ The blades are stuck (the blades are blocked or the motor shaft gets rusty);
■ The fan drive board operates improperly.
Troubleshooting:
"H9" Loss of
Synchronization Protection
for the Inverte r Fan
The fan drive board is
abnormal
Yes
Replace th e fan drive board
No
Whether th e U, V and W phases
of fan wires are conn ected pro perly?
Yes
No
Replace th e fan
Whether the resistance between
the windings of each phase for the fan is normal
(generally less than 10 ohms)? Whether the resistance values are
equal to each other? Is grounding insulation of the phase
windings of the fan normal (generally greater
than 2 megohms)?
Ye
s
Yes
Remove forei gn matters
Whether blades are stuck due to foreign
matters or rusting of motor shaft?
Yes
Yes
Replace th e faulty fan
Have other faults occurred
at the same time (for example, over-current
protection (H5), IPM module protection (H6),
start failure (HJ))?
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