Below 1 bar High

Baxi Below 1 bar Fault Code

Also written as BELOW1BAR — same fault.

The Baxi Below 1 bar fault code means: your boiler pressure is currently too low, which means it doesn't have enough water inside to circulate heat around your home.. It appears on 1 Baxi model in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: If the pressure falls below 1 bar it may indicate a leak on the central heating system.
Typical repair cost £70-130 (including labour)

DIY fix possible

Locate the external filling loop, usually two silver flexible hoses with valves attached under the boiler.Open the valves slowly to allow mains cold water into the system while watching the pressure gauge.Close the valves firmly once the needle sits in the green zone between 1 and 1.5 bar.

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Baxi models that show the Below 1 bar fault code

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

Source

Baxi Below 1 bar 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 27 April 2026