What does the Viessmann 06:... fault code mean?

Your boiler has detected that it is getting too hot and has automatically switched itself off to prevent potential damage.

How much does it cost to fix Viessmann error code 06:...?

Typical repair cost for the Viessmann 06:... fault is £150-350 including labour.

Maximum limit of the boiler water temperature, defaulted by the boiler coding card

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Each noise points to a different fault.

Sludge build-up — needs flushing, not bleeding.

Almost always a stuck diverter valve on combis.