INSIDE THE IPM MODULE THERE IS A SELF-PROTECTION MECHANISM AGAINST OVERCURRENT, OVERHEATING, ETC. WHENEVER IPM OVERCURRENT OR OVERHEATING HAPPENS, THE PINS (F0) WILL OUTPUT LOW VOLTAGE. WHEN THE MCU TESTS THE VOLTAGE (ó0.7V ), IT WILL SHUT DOWN THE AC UNIT, AND THE P0 PROTECTION WILL BE DISPLAYED. WHENEVER THE OVERCURRENT OR OVERHEATING IS RELIEVED, THE UNIT RECOVERS AND WILL WORK AUTOMATICALLY AGAIN.
REPAIR:
1) CHECK THE U/V/W WIRING CONNECTION AND SEE IF IT IS CORRECT
2) TAKE OUT THE WIRING OF U/V/W FROM COMPRESSOR AND TURN THE UNIT BACK ON. IF THE PROBLEM REMAINS THE SAME, PLEASE REPLACE THE OUTDOOR UNIT PCB
3) OVERLOAD PROTECTION:
3.1) CHECK THE OUTDOOR UNIT FAN MOTOR. IF THE FAN MOTOR IS IN LOW SPEED OR IT DOES NOT WORK, PLEASE REPLACE THE FAN MOTOR
3.2) THE COOLING SYSTEM IS NOT OK. CHECK IF THERE IS TOO MUCH GAS CHARGING, IF THE CAPACILLARY IS BLOCKED, IF THE EVAPORATOR OR CONDENSER ARE TOO DIRTY, IF THE COMPRESSOR WORKS ABNORMALLY?
4) CHECK IF THE INSULATION RESISTANCE OF THE COMPRESSOR IS TOO LOW. IF YES, PLEASE REPLACE THE COMPRESSOR
5) CHECK IF THE PCB IS THE CORRECT ONE BEING USED, MAYBE THE EEPROM DATA DOES NOT MATCH THE USED COMPRESSOR
6) CHECK IF THE COMPRESSOR HAS A FAULT SUCH AS A BLOCKED CYLINDER, A WINDING SHORT CIRCUIT OR OPEN CIRCUIT?
7) CHECK IF A HARDWARE FAILURE IS POSSIBLE. IF YES, IT IS USUALLY FROM THE PCB OR COMPRESSOR. PLEASE REPLACE IF NECESSARY
8) SWITCH OFF THE AC UNIT AND SWITCH IT BACK ON. IF THE COMPRESSOR DOES NOT WORK AND P0 IS DISPLAYED AT THE SAME TIME, PLEASE REPLACE THE OUTDOOR UNIT PCB
9) SWITCH OFF THE AC UNIT AND SWITCH IT BACK ON. IF THE COMPRESSOR DOES WORK AND P0 IS DISPLAYED AT THE SAME TIME, IT IS A PROBLEM OF THE IPM OVERHEATING OR OVERCURRENT