Mitsubishi Electric PUHY-P250YNW-A Service Handbook page 9

CONTENTS
Chapter 8 Troubleshooting Based on Observed Symptoms
8-1 MA Remote Controller Problems .......................................................................................................... 1
8-2 Refrigerant Control Problems ............................................................................................................... 5
8-3 External Input Problems (including operation mode)......................................................................... 8
8-4 Checking Transmission Waveform and for Electrical Noise Interference ........................................ 9
8-5 Pressure Sensor Circuit Configuration and Troubleshooting Pressure Sensor Problems .......... 12
8-6 Troubleshooting Solenoid Valve Problems ....................................................................................... 16
8-7 Troubleshooting Outdoor Unit Fan Problems ................................................................................... 18
8-8 Troubleshooting LEV Problems.......................................................................................................... 19
8-9 Troubleshooting Inverter Problems ................................................................................................... 25
8-10 Control Circuit ...................................................................................................................................... 40
8-11 Measures for Refrigerant Leakage ..................................................................................................... 43
8-12 Parts Replacement Instructions ......................................................................................................... 45
8-13 Troubleshooting Problems Using the LED Status Indicators on the Outdoor Unit ....................... 70
8-14 Replacement Instructions for Motor and Bearing (Indoor Unit) ...................................................... 71
8-15 Maintenance/Inspection Schedule...................................................................................................... 77
Chapter 9 USB Function
9-1 Service Overview.................................................................................................................................... 1
9-2 Operation Data Collection and Storage Functions ............................................................................. 4
9-3 Software Rewrite Function on the USB................................................................................................ 8
9-4 Maintenance LED Display and Troubleshooting ............................................................................... 10
Chapter 10 LED Status Indicators on the Outdoor Unit Circuit Board
10-1 LED Status Indicators ............................................................................................................................ 1
10-2 LED Status Indicators Table.................................................................................................................. 4
HWE17020 GB