How much does it cost to fix Chaffoteaux error code 8.12?

Typical repair cost for the Chaffoteaux 8.12 fault is £80-150 including labour.

8.12 High

Chaffoteaux 8.12 Fault Code

Q: What does the Chaffoteaux 8.12 fault code mean?

Your boiler has stopped working because the water pressure inside the heating system has dropped too low.

Also written as 812 — same fault.

The Chaffoteaux 8.12 fault code means: your boiler has stopped working because the water pressure inside the heating system has dropped too low.. It appears on 3 Chaffoteaux models in our database.

Technical description: Insufficient Water

Typical repair cost £80-150 (including labour)

DIY fix possible

Locate the filling loop, which is a silver braided hose with one or two valves connecting your boiler to the mains water supply.Open the valve(s) slowly to allow water into the system while watching the pressure gauge on the front of your boiler.Stop filling when the needle reaches the green zone, typically between 1 and 1.5 bar, then tightly close the valve(s).

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Chaffoteaux models that show the 8.12 fault code

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

Source

Chaffoteaux 8.12 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 27 April 2026