Furnace will not run; LED status light flashes nine times repeatedly.
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: Electrical work can be hazardous. If you are not comfortable using a multimeter, contact an electrician or HVAC technician.
Steps to check:
- Inspect power connection: Turn off the breaker. Remove the furnace electrical access cover and verify that the black (hot) wire is on the L (line) terminal and the white (neutral) is on the N terminal. The green or bare wire should be securely attached to ground.
- Check service switch/outlet: If the furnace is plugged into a receptacle, use a plug-in outlet tester to verify correct polarity and ground.
- Verify breaker panel wiring: Ensure the furnace circuit is on a single-pole breaker with neutral returning to the same panel.
When to call a technician: If polarity or grounding issues are found, or if you are unsure how to correct them safely, hire a licensed electrician or HVAC technician.