A11
De Dietrich Fan Start Failure

Boiler displays A11, no ignition, fan may not start

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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

Defective fan motor on De Dietrich premix burner, Blocked fan wheel, Faulty fan speed control on main PCB, Loose fan connector

How to Fix / Troubleshooting

Safety: Disconnect power before accessing the fan assembly. Moving parts can cause injury.

Steps:

  • Listen for fan: On a heat demand, you should hear the fan start. If silent, proceed with checks.
  • Inspect fan connector: Remove the front panel and locate the fan. Ensure the electrical connector is fully seated and wires are intact.
  • Check for obstruction: Spin the fan wheel gently by hand (power off). It should rotate freely without scraping. Remove any debris.
  • Reset boiler: Restore power and reset. If the fan still does not start, do not bypass safety circuits.

Technician tasks: A professional should test the fan supply voltage, replace the fan assembly if seized, or replace the main PCB if it does not command the fan.

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Repair Difficulty

Hard 4/5

Required Part

Flue Fan Assembly
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