BoilerFaultCodesAtag A6 Fault Code
The Atag A6 fault code means: your boiler has detected that the water pressure inside the system is currently too low to operate safely.. It appears on 1 Atag model in our database.
Technical description: Water pressure
DIY fix possible
Locate the filling loop (a silver flexi-hose) beneath the boiler.Open the valves on the filling loop to allow cold mains water into the system.Watch the pressure gauge on the boiler until the needle reaches between 1.0 and 1.5 bar, then securely close the valves.
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Atag models that show the A6 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Atag A6 fault code information on this page is sourced and cross-checked against the official Atag service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026