Rheem
Short Cycling Due to Overheating or Flame Loss
Furnace short cycles: starts, heats briefly, then shuts off and restarts frequently
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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, Oversized furnace for duct system, Weak flame sensor, High limit switch opening
How to Fix / Troubleshooting
Safety first: Turn off power before removing panels or filters.
- Replace filter: Install a clean filter and ensure it is the correct size and not overly restrictive.
- Check vents: Open all supply registers and return grilles. Remove obstructions like rugs or furniture.
- Clean flame sensor: If burners light but shut off after a few seconds, clean the flame sensor as described in earlier entries.
- Monitor operation: After corrections, run the furnace for at least 15–20 minutes and observe. If it still short cycles, a professional should check heat exchanger temperature rise and gas input.
Persistent short cycling can reduce efficiency and damage components over time.
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Repair Difficulty
Medium
3/5
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