Indoor unit displays F8 and system may shut down under heavy load
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Possible Causes
How to Fix / Troubleshooting
Safety first: Turn off power to the outdoor unit. The inverter module carries lethal voltages even after shutdown; capacitors may hold charge.
Steps to try:
- Improve ventilation: Ensure at least the manufacturer-recommended clearance (often 12–24 inches) around the outdoor unit. Remove obstructions and vegetation.
- Clean outdoor coil: Rinse the coil with low-pressure water to remove dirt and lint that trap heat.
- Check fan operation: Confirm the outdoor fan runs at appropriate speed when the compressor is operating.
- Allow cool-down: After an F8 event, leave the system off for 30 minutes to allow the inverter to cool, then restart.
When to call a pro: Repeated F8 faults suggest an internal inverter module or sensor problem that requires board-level service or replacement.
Repair Difficulty
Required Part
We may earn a commission from links on this page.