18
Biasi
Fan Speed / Tachometer Fault
Error 18; heater may start but then shuts down with a fan-related fault.
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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
Faulty fan speed sensor, Fan motor failure, Loose fan connector, PCB fan control fault
How to Fix / Troubleshooting
Safety: Isolate power before accessing the fan compartment.
Steps:
- Inspect fan connector: Ensure the multi-pin plug to the fan is fully seated and free of corrosion.
- Check fan blades: Spin the fan gently by hand (power off). It should rotate freely without scraping.
- Listen during startup: Restore power and call for heat. If the fan hums, grinds, or fails to reach speed, it likely needs replacement.
Note: Fan replacement and verification of correct operation should be done by a qualified technician due to combustion safety implications.
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Repair Difficulty
Hard
4/5
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