CRITICAL URGENCY

York 5 Red Flashes — Roll Out Switch Open (SAFETY)

5 red flashes

Flame rollout switch tripped — possible cracked heat exchanger and CO risk.

Brand: York (Also covers Coleman, Luxaire) | Equipment: Gas Furnace

What This Code Means

5 red flashes means the flame rollout switch has opened. Flames are escaping the burner enclosure — a serious combustion problem.

Likely Causes (Ranked)

Common and serious

Cracked heat exchanger

What: Crack lets flames escape.

How to check: Tech inspection only.

Fix: Replace HX or furnace.

Shop parts

Common on 90%+ AFUE

Plugged secondary HX

What: Condensate buildup blocks passages.

How to check: Tech inspection.

Fix: Clean or replace.

Shop parts

Common

Blocked flue

What: Birds, ice, dropped pipe.

How to check: Inspect exhaust.

Fix: Clear.

Shop parts

Less common

Failed inducer

What: Poor draft.

How to check: Listen.

Fix: Replace.

Shop parts

Diagnostic Steps

STOP — don't keep resetting
Shut off gas
Verify CO detector
Call licensed HVAC tech

Frequently Asked Questions

Can I reset and keep running?

No — CO risk with cracked heat exchanger.

Cost to repair?

Heat exchanger $500-1200 labor; often cheaper to replace furnace.

Same on Coleman/Luxaire?

Yes.

Related York Codes

Related Symptoms

Need More Help?

Try our interactive symptom diagnostic tool or browse York parts.

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York 5 Red Flashes — Roll Out Switch Open (SAFETY)

What This Code Means

Likely Causes (Ranked)

Cracked heat exchanger

Plugged secondary HX

Blocked flue

Failed inducer

Diagnostic Steps

Frequently Asked Questions

Related York Codes

Related Symptoms

Need More Help?