33
Ducane Limit or Rollout Open During Operation

Code 33, limit or rollout switch open, furnace shuts down mid-cycle

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Overheating due to restricted airflow, Tripped rollout switch from flame disturbance, Dirty heat exchanger on Ducane furnace, Failed circulating blower motor or capacitor

How to Fix / Troubleshooting

Critical safety: Rollout events can indicate serious combustion issues. Turn off gas and power until inspected.

  • Step 1 – Check filter and airflow: Replace dirty filters, open registers, and ensure return air is not blocked.
  • Step 2 – Inspect blower: Confirm the blower starts promptly and runs at full speed. Listen for humming or slow start that may indicate a bad capacitor or motor.
  • Step 3 – Check rollout switches: Look for manual-reset rollout switches near burners. If tripped, press reset once. If they trip again, stop using the furnace and call a professional.
  • Step 4 – Professional inspection: A technician should inspect the heat exchanger, burners, and venting for cracks, soot, or blockages.
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Repair Difficulty

Professional Required 5/5

Required Part

Flame Rollout Switch
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