Viessmann · Vitodens 100-W Boiler
The burner is in a fault state because of a memory access checksum error in the BCU. This indicates an integrity issue with the control unit's memory.
Click steps to track your progress.
Reset the boiler by briefly turning off and on its power supply.
If the fault recurs, contact a qualified heating engineer for further diagnosis.
An engineer may need to replace the BCU burner control unit if the issue persists.