Gree                GMV6 DC Inverter VRF Units Service Manual 
 
2.138 "U0" Insufficient Warm-up Time for Compressor 
Fault display: main board of outdoor unit, wired controller of indoor unit and receiver of indoor unit 
display   
Fault diagnosis: 
When the oil preheating period of time before compressor starts is less than eight hours, the unit 
generates a fault. 
Possible causes: -- 
Troubleshooting: Warm up the whole unit for more than eight hours before startup. 
2.139 "U2" Incorrect Settings of Outdoor Unit Capacity DIP 
Switch/Jumper Cap 
Fault display: main board of outdoor unit, wired controller of indoor unit and receiver of indoor unit 
display   
Applicable models: all outdoor units 
Fault diagnosis: 
When the capacity DIP switch detected by the outdoor unit's main board is inconsistent with the unit's 
actual capacity, or the jumper cap value detected by the outdoor unit's main board is inconsistent with 
the actual unit, the fault is generated. 
Possible causes: 
■ Capacity DIP switch error or jumper cap error (for some models without jumper caps, jumper cap 
error is not detected) 
■ DIP switch or jumper cap is broken 
■ Abnormal detection circuit 
Troubleshooting: 
"U2" Inco rrect Settings of 
Outdoo r Unit Capaci ty DIP 
Switch/Jumper Ca p
The  detection  circuit may 
operate  impro perly
Yes
Whether capacity DIP switch 
on the main board and jumper cap are 
consistent with the actual units?
No
Replace  the main control 
board
No
After the unit is powered 
off, dial the DIP switch 
again o r re place the jumper 
cap and then power on the 
unit again