E12
Weishaupt Control Communication Fault

Boiler shows E12, communication error between burner control and main boiler control.

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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

Loose communication harness between Weishaupt burner control and boiler PCB, Faulty burner control module, Faulty main control board, Electrical interference or incorrect grounding

How to Fix / Troubleshooting

Safety first: Disconnect power before unplugging or plugging any control cables.

  • Check communication cable: Locate the multi-core cable between the burner control (e.g. W-FM module) and the boiler control. Ensure all plugs are fully seated and locking clips engaged.
  • Inspect for damage: Look for crushed, cut, or overheated cables. Replace damaged harnesses with genuine Weishaupt parts.
  • Power cycle: After checking connections, restore power and perform a controlled restart of both the burner control and boiler control according to the manual.
  • Check grounding: Verify that the boiler and burner are properly earthed and that there are no loose earth connections that could cause interference.

When to call a professional: If communication errors persist, a technician with Weishaupt diagnostic tools should test the burner control and main PCB.

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Repair Difficulty

Hard 4/5

Required Part

Burner Control Module (Weishaupt W-FM)
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