GREE                                                                        GMV5E DC INVERTER VRF UNITS SERVICE MANUAL 
    127   
compressor's drive board. If the fault is solved, the 
compressor's drive board is faulty. 
Communication 
failure between 
main control board 
and variable 
frequency fan drive 
1.The communication cable is not 
connected. 
2.The communicator is 
disconnected. 
3.The communication cable is 
poorly connected. 
4.The communicator is faulty. 
1)Check if the cable connecting the fan's drive 
board and the compressor's drive board is loose. If 
yes, reconnect it; 
2)Check if the cable connecting the fan's drive 
board and compressor's drive board is broken. If 
yes, replace the cable;   
3)Check the contact of the communication cable 
connecting the fan's drive board and compressor's 
drive board;   
4)Replace the control board. If the fault is solved, 
the control board is faulty. Replace the fan's drive 
board. If the fault is solved, the fan's drive board is 
faulty. 
Malfunction of lack 
of indoor unit 
1.Some indoor units in the system 
are not power-connected. 
2.Communication wires of some 
indoor units in the system are 
disconnected or have loose 
contact. 
3.Controllers of some indoor units 
in the system are abnormal. 
1. Check the number of online indoor units through 
outdoor unit and compare it with the number of 
indoor units that are actually installed. Confirm the 
number of missing indoor units. 
2. Check whether all the indoor units are 
power-connected. If some are not, connect them 
to power. If power connection is fine, check further 
whether there is any indoor unit that fails to display 
on wired controller or receiver board. If such 
indoor unit exists, it means its main board is 
abnormal and needs to be replaced. If everything 
said above is confirmed OK, continue to check 
according to step 3. 
3. The missing indoor units will display error “C0” 
on wired controller or receiver board. Check the 
communication wire of the missing indoor unit 
whether it is disconnected or has loose contact. If 
yes, connect the communication wire tightly. If 
communication wire is OK, check whether it is 
connected reversely. Power on the indoor unit 
again and see if error “C0” occurs. If “C0” is 
displayed, it means main board is abnormal and 
needs to be replaced. 
Indoor unit project 
number conflict 
warning 
1.Project numbers conflict with 
each other. 
1.Change conflicting project numbers and ensure 
that no IDU's project number is repeated.   
Outdoor unit 
number 
inconsistency 
warning 
1.Communication cables between 
ODUs are loose. 
2.Communication cables between 
ODUs are broken. 
3.Communication cables between 
ODUs are poorly connected. 
4.The control board is faulty. 
1.If the communication cable is loose, reconnect it;   
2.If the communication cable is broken, replace it; 
3.Check contact of the communication cable; 
4.Replace the control board.   
The SA8 dial switch of the ODU is 
not switched to 00. 
The SA8 dial switch of the ODU is 
faulty. 
1.Switch the SA8 dial switch of an ODU to 00; 
2.Replace the control board or switch an ODU's 
SA8 dial switch to 00.   
Multiple controlling 
units 
SA8 dial switches of multiple 
ODUs are switched to 00. 
Dial switches of multiple ODUs 
are faulty. 
1.Leave one SA8 dial switch unchanged, while 
switch all the other dial switches to 11; 
2.Replace the control board.   
The master IDU is powered off. 
The communication of the master 
Check if the master IDU is powered on. If yes, 
replace the main board;