What does the Chaffoteaux YELLOW FLAMES SOOT FORMED fault code mean?

Your boiler is not burning fuel correctly, which is causing soot buildup and indicates a significant safety risk from potentially harmful gases.

How much does it cost to fix Chaffoteaux error code YELLOW FLAMES SOOT FORMED?

Typical repair cost for the Chaffoteaux YELLOW FLAMES SOOT FORMED fault is £150-300 including labour.

i) Heating body fins blocked, ii) Primary air supply restricted, iii) Wrong injectors

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.