BoilerFaultCodesChaffoteaux 2a Fault Code
Also written as 2A — same fault.
The Chaffoteaux 2a fault code means: your boiler is making loud noises because the water pressure inside your heating system has dropped too low to operate correctly.. It appears on 3 Chaffoteaux models in our database.
Technical description: Boiler noisy - Low pressure in sealed system
DIY fix possible
Locate the external filling loop, which is a silver braided hose with one or two valves located underneath your boiler.Gradually open the valve(s) to allow mains water into the system while watching the pressure gauge on the front panel.Stop filling once the needle reaches the green zone, typically between 1.0 and 1.5 bar, and ensure the valves are fully closed.
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Gas Safe Register →Chaffoteaux models that show the 2a fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Chaffoteaux 2a 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