6 FLASH
Armstrong Air
Soft Lockout / Reversed Line Polarity or Ground Fault
Furnace will not start; LED flashes 6 times repeatedly on Armstrong Air furnace board.
Advertisements
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.
Advertisements
Possible Causes
Line and neutral reversed at furnace power connection, Missing or poor equipment ground, Shared neutral with other loads causing noise, Control board sensing error
How to Fix / Troubleshooting
Safety: This involves line-voltage wiring. If you are not comfortable working with 120 VAC, contact a licensed electrician or HVAC technician.
Steps to check:
- Verify power source: Turn off the furnace breaker. Remove the electrical access cover on the furnace. Confirm that the hot (usually black) wire is connected to the L (line) terminal and the neutral (usually white) is connected to the N terminal on the furnace junction or control board.
- Check ground connection: Ensure the green or bare copper ground wire is securely attached to the furnace chassis ground screw.
- Inspect for shared neutrals: If the furnace circuit shares a neutral with other loads, electrical noise can interfere with flame sensing and board operation. Ideally, the furnace should be on a dedicated circuit.
- Reset power: After correcting wiring, restore power and observe the LED. If the 6-flash code persists, the control board may be damaged and require replacement.
Advertisements
Repair Difficulty
Hard
4/5
Required Part
Integrated Furnace Control Board
Check Price on Amazon
We may earn a commission from links on this page.
Advertisements