Miller
High Limit Cycling / Overheating
Furnace short cycles: burners light for 30–90 seconds, then shut off, then restart repeatedly.
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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
Dirty air filter, Undersized or blocked return duct, Closed supply registers, Weak blower motor or failing capacitor
How to Fix / Troubleshooting
Safety: Turn off power before accessing blower or filter compartments.
- Replace filter: Remove and inspect the furnace filter. Replace if dirty or restrictive. Use a filter type recommended for Miller furnaces.
- Open airflow paths: Ensure all supply registers and return grilles are open and unobstructed. Check for crushed or kinked flex ducts.
- Inspect blower performance: Listen for unusual noises or slow start. Test the blower capacitor and replace if out of spec. Replace the blower motor if it overheats or fails to reach full speed.
- Monitor operation: After corrections, run the furnace and verify longer, stable heating cycles without frequent burner shutdowns.
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Repair Difficulty
Medium
3/5
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