P x.x Low

Atag P x.x Fault Code

Also written as PXX — same fault.

The Atag P x.x fault code means: your boiler is providing a live reading of the current water pressure in your heating system, which is a standard status display rather than a fault.. It appears on 4 Atag models in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: Water pressure in bar

DIY fix possible

Check the pressure gauge on the front of the boiler display.Ensure the reading is between 1.0 and 1.5 bar while the heating is off.If the reading is outside this range, use the external filling loop to adjust the pressure.

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Atag models that show the P x.x fault code

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

Source

Atag P x.x 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 27 April 2026