BoilerFaultCodesWhat the manual says
Manufacturer manualInternal fault
From this model's manual
Verified against the Worcester Bosch Greenstar 8000 Life Style installation & service manual, page 79.
What causes this fault?
This fault occurs when the boiler's central control system suffers a communication breakdown between its internal electronic components. It is typically caused by a critical failure within the main circuit board or the digital display unit, meaning the boiler can no longer safely manage the heating process. In some cases, a sudden power surge or moisture ingress can damage these sensitive parts, leading to a complete system freeze.
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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