GREE                                                                        GMV5E DC INVERTER VRF UNITS SERVICE MANUAL 
    238   
 
(2) Restoring  AP1  Engineering  Parameters  to  Factory  Settings  (This  Step  Is  Not  Required  for 
Original Packaged Parts) 
After wiring, whatever the AP1 is a master IDU AP1 or a slave IDU AP1, the new AP1 must be 
restored to factory settings. There are three methods to restore engineering parameter settings: 
① If the IDU is configured with wired control, set P35 and P36 to default values.   
② If the IDU is configured with wireless control, use the special control YV1L1 to set P35 and P36 
to default values. 
③ If the IDU is configured with wireless control and special control, you can restore engineering 
settings  through  the AP1  SW1  button. After  AP1 is  powered  on,  press and  hold  SW1 for  5 
seconds. If a tick sound is heard, release the button.   
 
(3) Cautions on Replacement of Master IDU AP1 
If the AP1 of the master IDU needs to be replaced, after the IDU is powered on, “No master IDU 
(L7)” or “Project number conflict (C5)” alarm may be reported.   
① Troubleshoot for “no master IDU (L7)” fault