What does the Viessmann F1 fault code mean?

Your boiler has detected that the exhaust gases leaving your home are becoming dangerously hot and has shut itself down to prevent damage.

How much does it cost to fix Viessmann error code F1?

Typical repair cost for the Viessmann F1 fault is £150-350 including labour.

Max. flue gas temperature reached

This is a emergency 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.

Safety-critical — turn off, read this.