Mitsubishi Electric HP120TNU-A Service Handbook page 11

CONTENTS
Chapter 8 Troubleshooting Based on Observed Symptoms
8-1 MA Remote Controller Problems .......................................................................................................... 1
8-2 ME remote Controller Problems ........................................................................................................... 5
8-3 Refrigerant Control Problems ............................................................................................................. 10
8-4 Checking Transmission Waveform and for Electrical Noise Interference ...................................... 15
8-5 Pressure Sensor Circuit Configuration and Troubleshooting Pressure Sensor Problems .......... 18
8-6 Troubleshooting Solenoid Valve Problems ....................................................................................... 22
8-7 Troubleshooting Outdoor Unit Fan Problems ................................................................................... 23
8-8 Troubleshooting LEV Problems.......................................................................................................... 24
8-9 Troubleshooting Problems with Major Components on BC Controller .......................................... 30
8-10 Troubleshooting Inverter Problems ................................................................................................... 44
8-11 Control Circuit ...................................................................................................................................... 57
8-12 Measures for Refrigerant Leakage ..................................................................................................... 63
8-13 Parts Replacement Instructions ......................................................................................................... 65
8-14 BC Controller Maintenance Instructions............................................................................................ 97
8-15 Troubleshooting Problems Using the LED Status Indicators on the Outdoor Unit ..................... 100
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
HWE18220_GB