Indoor unit stops, E8 displayed, often associated with abnormal compressor operation

Safety first: This fault involves high-voltage inverter circuits and refrigerant pressures. Only qualified personnel should perform electrical and refrigeration diagnostics. Always isolate power at the disconnect.

• Basic homeowner checks:
  • Ensure outdoor coil is clean and free of leaves, dirt, or obstructions. Gently hose from inside out if dirty.
  • Verify that outdoor fan is running when the compressor is commanded on.
• Technician checks (summary):
  • Measure compressor winding resistance and insulation resistance to ground.
  • Check inverter DC bus voltage and output waveforms.
  • Verify system pressures and superheat/subcooling to rule out severe overcharge or blockage.
• Likely repairs: If the compressor is shorted or locked, the outdoor unit (compressor and possibly coil) may need replacement. If the compressor tests good but E8 persists, the inverter power module or outdoor PCB is suspect.
• Do not bypass protections: Never attempt to bypass overloads or safety circuits; this can cause fire or compressor explosion.