Carrier Furnace Error Code 33: Limit Switch / Flame Rollout Open
Primary high temperature limit switch opened due to furnace overheating or airflow restriction.
Equipment TypeResidential Gas Furnace & Air HandlerBrand: Carrier
Fault SeverityCriticalSystem Lockout Active
Estimated Repair Cost$30 – $380Parts & Certified Labor
🚨 Symptoms of Carrier Error Code 33
- Blower motor runs continuously but burners shut off
- Status LED blinks 3 rapid flashes then 3 slow flashes (Code 33)
- No heat coming from air vents
🔍 Root Causes for Carrier Code Code 33
- Extremely dirty furnace air filter choking airflow
- Blocked or closed supply vents and return air grilles
- Failing blower motor capacitor or dead blower motor
- Cracked heat exchanger tripping rollout switch
🛠️ How to Reset & Troubleshoot Carrier Error Code 33
- Turn off furnace power and replace air filter immediately
- Check all room registers and ensure return grilles are unblocked
- Allow furnace to cool down for 20 minutes and reset circuit breaker
- Have a certified HVAC technician inspect the heat exchanger for cracks
Frequently Asked Questions — Carrier Code Code 33
What does Carrier error code Code 33 mean?
Carrier code Code 33 indicates: Primary high temperature limit switch opened due to furnace overheating or airflow restriction.
How do I reset error code Code 33 on Carrier?
Turn off the electrical circuit breaker or isolator to the unit for at least 5 minutes to discharge the capacitors and reset the microprocessor. If the code reappears immediately upon restarting, professional inspection is required.
What causes error code Code 33 on Carrier systems?
Common triggers include: Extremely dirty furnace air filter choking airflow, Blocked or closed supply vents and return air grilles, Failing blower motor capacitor or dead blower motor.