1 09 Emergency

Chaffoteaux 1 09 Fault Code

Also written as 109 — same fault.

The Chaffoteaux 1 09 fault code means: your boiler has detected that the water pressure inside your heating system is too high and has shut down for safety.. It appears on 1 Chaffoteaux model in our database.

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

Technical description: Pression installation > 3 bar
Typical repair cost £80-150 (including labour)

DIY fix possible

Locate the radiator closest to the boilerOpen the bleed valve on that radiator to release water into a containerMonitor the pressure gauge on the boiler until it drops back into the green zone (usually 1.0 to 1.5 bar)Close the bleed valve tightly

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Chaffoteaux models that show the 1 09 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Chaffoteaux 1 09 fault code information on this page is sourced and cross-checked against the official Chaffoteaux service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026