BoilerFaultCodesPro low-pressure Fault Code
Also written as LOWPRESSURE — same fault.
The Pro low-pressure fault code means: your boiler has stopped working because the water pressure inside the system has dropped too low to allow it to run safely.. It appears on 1 Pro model in our database.
Technical description: Insufficient system pressure (min. 0.5 bar) preventing the pump and fan from operating.
DIY fix possible
Locate the filling loop (usually a silver braided hose with small valves under the boiler).Slowly open the valve(s) until you hear water entering the system and watch the pressure gauge rise.Close the valves tightly once the pressure gauge reaches between 1.0 and 1.5 bar.
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Pro models that show the low-pressure fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Pro low-pressure fault code information on this page is sourced and cross-checked against the official Pro service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026