BoilerFaultCodesWhat the manual says
Manufacturer manualElectronic fault | Electronics defect
From this model's manual
Verified against the Vaillant Turbomax Plus 824 828e installation & service manual, page 40.
What causes this fault?
This fault occurs when the boiler's main control board fails to verify the flame signal or encounters an internal processing error. It is essentially a communication breakdown between the electronic 'brain' and the ignition system, often caused by worn-out components or moisture damage on the circuitry.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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