What does the Chaffoteaux 9.iii fault code mean?

Your boiler is heating up too quickly because it is burning too much gas at once, causing it to shut down for safety.

How much does it cost to fix Chaffoteaux error code 9.iii?

Typical repair cost for the Chaffoteaux 9.iii fault is £120-250 including labour.

Excessive temperature rise across boiler - Gas rate too high

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.

Older boilers — thermocouple, draught, gas supply.

Sludge build-up — needs flushing, not bleeding.