HIGH URGENCY

Trane Furnace 6 Flashes — Line Voltage Polarity Incorrect

6 flashes

Line voltage polarity incorrect — wiring or transformer fault.

Brand: Trane (Also covers American Standard) | Equipment: Gas Furnace

What This Code Means

6 flashes means the line voltage (115VAC) coming into the furnace has reversed polarity. Hot and neutral wires are swapped, or there's a grounding issue.

Likely Causes (Ranked)

Most common

Reversed hot/neutral wires

What: Hot and neutral are swapped at the disconnect, junction box, or in the home wiring.

How to check: Electrician tests outlet/wiring polarity.

Fix: Correct wiring.

Less common

Faulty transformer

What: Internal transformer fault causes polarity-like fault.

How to check: Tech tests transformer output.

Fix: Replace transformer.

Shop parts

Less common

Bad control board

What: Board incorrectly reads polarity.

How to check: Tech diagnostic.

Fix: Replace board.

Shop parts

Diagnostic Steps

Cut power at the breaker
Have a licensed electrician check wiring polarity
Verify ground connection
If wiring checks out, call HVAC tech

Frequently Asked Questions

Is Trane 6 flashes dangerous?

It indicates an electrical wiring problem. Have a licensed electrician check before operating.

Can I fix this myself?

Only if you're qualified to work on line voltage wiring.

Same on American Standard?

Yes — same control system.

Related Trane Codes

Related Symptoms

Need More Help?

Try our interactive symptom diagnostic tool or browse Trane parts.

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