HIGH URGENCY

Lennox 9 Flashes — Line Voltage Polarity Incorrect

9 flashes

Line voltage polarity reversed — wiring or grounding issue.

Brand: Lennox (Also covers Armstrong Air, Aire-Flo, Ducane) | Equipment: Gas Furnace

What This Code Means

9 flashes means the incoming 115VAC line voltage has reversed polarity or there's a grounding issue.

Most common

What: Wires swapped at outlet, disconnect, or junction.

How to check: Electrician tests polarity.

Fix: Correct wiring.

Common

What: Improper or missing ground connection.

How to check: Electrician verifies ground.

Fix: Restore proper ground.

Can I fix Lennox 9 flashes?

Only if qualified for line voltage work. Otherwise call an electrician.

Will it damage the furnace?

Can damage control board over time and create shock hazard.

Same on Armstrong?

Yes.