A08
Beretta Fan Speed / Tachometer Fault

Furnace shows A08, burner does not start, may be accompanied by abnormal fan behavior

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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 flue fan speed sensor, Damaged fan motor, Loose fan tachometer wiring, Faulty control board fan driver

How to Fix / Troubleshooting

Safety: Disconnect power before touching any fan wiring or components.

  • Visual inspection of flue fan: Access the flue fan assembly. Check the multi-pin connector between the fan and the Beretta control board. Reseat the connector and inspect for corrosion or burnt pins.
  • Check fan wheel: Ensure the impeller is not rubbing the housing and that it spins freely. Remove any debris.
  • Inspect tachometer wiring: Many Beretta fans have a separate tachometer (speed feedback) wire. Verify it is not cut or pinched.
  • Test operation: Restore power and call for heat. If the fan does not start or runs erratically before A08 appears, the fan assembly likely needs replacement.

Fan speed control and feedback are safety-critical; replacement should be done by a qualified technician.

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Repair Difficulty

Hard 4/5

Required Part

Flue Fan Assembly
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