What does the Chaffoteaux 13 fault code mean?

Your boiler is picking up excess water pressure, which suggests water is leaking internally into the heating system where it shouldn't be.

How much does it cost to fix Chaffoteaux error code 13?

Typical repair cost for the Chaffoteaux 13 fault is £150-300 including labour.

Gain in pressure shown on gauge - Filling loop letting by or secondary heat exchanger leak

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

Six most common causes of dropping pressure.

Almost always a stuck diverter valve on combis.

Step-by-step using the filling loop.