V4+R VRF 50/60Hz 
201608    77 
Part 5 - Diagnosis and Troubleshooting 
4.15 P1 Troubleshooting 
 Digital display output 4.15.1
   
 
 Description 4.15.2
  Discharge  pipe  high  pressure  protection. When the discharge  pressure  rises  above 4.4MPa, the  system  displays  P1 
protection and  all units stop running. When  the discharge pressure falls below 3.2MPa, P1  is removed and normal 
operation resumes.   
  If  the  system  has  a  3-phase  protector  and  the  3-phase  protector  is  connected  with  the  high  pressure  switch,  the 
system will display P1 protection when initially powered on, and P1 protection will disappear once the system reaches 
a steady state. 
  Error code is only displayed on the unit with the error. 
 
 Possible causes 4.15.3
  Outdoor unit stop valves are closed. 
  Pressure sensor/switch not connected properly or has malfunctioned. 
  Excess refrigerant. 
  System contains air or nitrogen. 
  High pressure side blockage. 
  Poor condenser heat exchange. 
  Main PCB damaged. 
 
 Procedure 4.15.4
 
ODU stop valves are closed 
High pressure sensor connection on main 
PCB is loose
1
 
Ensure the sensor is connected properly 
High pressure sensor has short-circuited 
or failed
2
 
Discharge part of the refrigerant. Add oil 
if it leaks during discharge 
Flowchart  continued  on  next  page  …