BoilerFaultCodesBaxi I Fault Code
The Baxi I fault code means: your boiler has stopped because the water pressure inside the heating system is either too low or too high.. It appears on 5 Baxi models in our database.
Technical description: CH system pressure less than 0.5 bar or greater than 2.7 bar on digital display
DIY fix possible
Locate the filling loop valves connected to your boiler.If the pressure is below 0.5 bar, slowly open the valves to let water in until the gauge reads between 1.0 and 1.5 bar, then close them tightly.If the pressure is above 2.7 bar, bleed a radiator to let out excess water until the pressure drops back into the normal range.
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Baxi models that show the I fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Baxi I fault code information on this page is sourced and cross-checked against the official Baxi service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026