Carrier Error Code 33: Flame Rollout Switch Solutions Guide

Quick Answer — Carrier Error Code 33 (2025)

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Error code 33 on Carrier furnaces means the flame rollout switch has tripped—flames are escaping the combustion chamber.

The most common causes are blocked vents (40 %), cracked heat exchangers (30 %), and dirty burners (15 %).

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This fault is extremely dangerous because it can lead to fire or carbon-monoxide exposure.

Typical repairs cost $400–$600 and take 2–4 hours; heat exchanger replacement runs $1 500–$2 500 and can take up to 6 hours.

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Turn off the furnace immediately and contact Fixair emergency service for same-day diagnosis and repair.

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What Does Carrier Error Code 33 Mean?

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The flame rollout switch protects the furnace from unsafe combustion. When flames leave the sealed chamber, the switch cuts power to stop fuel flow.

This shutdown prevents fire and carbon-monoxide release. The furnace will not restart until a technician resets the safety system after repairs.

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Common Causes of Error 33

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1. Blocked vent or intake (≈ 40 %) — ice, debris, or bird nests restrict airflow.
2. Cracked heat exchanger (≈ 30 %) — age and metal fatigue let flames and CO escape.
3. Dirty burners (≈ 15 %) — soot and dust distort flame pattern.
4. Incorrect gas pressure (≈ 10 %) — leads to unstable combustion.
5. Failed inducer motor (≈ 5 %) — insufficient draft traps flue gases.

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Immediate Safety Steps

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1. Shut off furnace power at the switch or breaker.
2. Close the gas valve (handle perpendicular to pipe).
3. Open windows for ventilation.
4. If you smell gas, evacuate and call 911.
5. Contact Fixair for professional diagnostic service.

Never reset or bypass the rollout switch yourself.

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Repair Costs and Timelines (2025)

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Most error 33 repairs fall between $400 and $600, including diagnosis and labor.

Common tasks and ranges: vent clearing $100–$250, burner cleaning $200–$350, inducer motor $350–$750, heat exchanger $1 500–$2 500.

Average completion time is 2 to 6 hours, depending on parts and furnace age.

Fixair provides upfront pricing and same-day completion for most cases.

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Prevention Tips

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• Schedule annual professional maintenance ($150–$300).
• Replace filters monthly in heating season.
• Keep exterior vents clear of snow or debris.
• Install carbon-monoxide detectors on each floor.
• Act immediately if flames turn yellow or produce soot.

Preventive maintenance reduces rollout faults by over 80 %. Fixair’s maintenance plan offers priority service and discounted repairs.

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Frequently Asked Questions

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Is Carrier error code 33 dangerous?

Yes. Flames leaving the combustion chamber create immediate fire and CO hazards. Shut off the unit and contact a professional.

Can I fix it myself?

No. This involves gas and combustion controls requiring certified testing equipment.

How much does it cost to repair?

Average $400–$600; vent issues on the low end, heat exchangers up to $2 500.

How long does it take?

Minor repairs 1–2 hours; major component replacement up to 6 hours.

Will it return?

Not if the root cause is addressed and maintenance is performed annually.

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Summary

Error code 33 is one of the most critical Carrier safety alerts. It means flames have escaped the combustion zone and the system shut down to prevent fire or CO exposure.

Turn off the furnace and schedule professional service immediately.

Most repairs are resolved within a single day for under $600.