What does the Ferroli F04 fault code mean?

Your boiler has detected that the exhaust gases are becoming too hot, so it has safely shut itself down to prevent damage.

How much does it cost to fix Ferroli error code F04?

Typical repair cost for the Ferroli F04 fault is £120-250 including labour.

Flue gas thermostat trip/Flue gas temperature fualt

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.

Work through these before the call-out.

Sludge build-up — needs flushing, not bleeding.