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richardsmichaelSep 18, 2025
Why is my Viessmann Boiler showing error code A8?
- SSamantha FreemanSep 18, 2025
If your Viessmann Boiler is showing error code A8, it indicates an air lock in the internal circulation pump or that the minimum flow rate is not achieved. If the fault message continues to be displayed, vent the system.











