A05
Beretta Flue Gas Pressure / Draft Fault

Display shows A05, furnace stops, may occur during strong wind or poor draft conditions

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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

Blocked or partially blocked flue, Faulty air pressure switch, Cracked or disconnected pressure tubing, Weak flue fan

How to Fix / Troubleshooting

Safety: Switch off power and gas. Flue and draft issues can cause carbon monoxide hazards.

  • Inspect flue terminal and intake (for balanced flue models): Ensure both exhaust and air intake terminals are free of obstructions, snow, or insect screens clogged with debris.
  • Check pressure switch tubing: Open the combustion compartment and locate the air pressure switch connected to the flue fan by silicone tubes. Inspect tubes for splits, kinks, or water inside. Replace damaged tubes and drain any condensate.
  • Verify pressure switch connections: Ensure the electrical connectors on the Beretta air pressure switch are tight. Do not adjust the calibration screw.
  • Test operation: Restore power and call for heat. Listen for the flue fan; if it runs but A05 appears, the pressure switch or fan performance may be faulty and require professional testing.

Do not bypass or short the pressure switch; this is a critical safety device.

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Repair Difficulty

Hard 4/5

Required Part

Air Pressure Switch
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