What does the Viessmann 21:1 to 21:100 fault code mean?

Your boiler is reminding you that it is due for its routine annual safety service based on the number of hours it has been running.

How much does it cost to fix Viessmann error code 21:1 to 21:100?

Typical repair cost for the Viessmann 21:1 to 21:100 fault is £100-£180 including labour.

The number of hours run before the burner should be serviced is adjustable from 100 to 10000 hours (each step represents 100 hours)

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Break-even maths on monthly cover.

7 signs repair isn't worth it anymore.

Realistic UK prices for a swap.