What does the Viessmann 25:1 fault code mean?

Your boiler has lost the connection to the thermometer placed outside your home, so it cannot automatically adjust your heating based on the weather.

How much does it cost to fix Viessmann error code 25:1?

Typical repair cost for the Viessmann 25:1 fault is £120-200 including labour.

Recognition of outside temperature sensor and fault monitoring

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

Safety-critical — turn off, read this.

Break-even maths on monthly cover.

7 signs repair isn't worth it anymore.