Carrier Code 34
Rollout Limit Switch Trip
What Carrier Code 34 Means
Rollout Limit Switch Trip – Furnace shuts down after brief operation
Common Causes
- Heat exchanger clogged with dust
- Airflow blocked by dirty filter
- Furnace temperature too high
- Rollout switch stuck open
- Combustion air restricted
First-Check: Step-by-Step Troubleshooting
- Replace furnace air filter immediately
- Check all vents unobstructed
- Inspect heat exchanger for clogging
- Clean around furnace blower area
- Reset rollout switch manually
- Clear combustion air intake
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