BoilerFaultCodesKeston Water Pressure Fault Code
Also written as WATERPRESSURE — same fault.
The Keston Water Pressure fault code means: your boiler has stopped working because the amount of water inside your heating system has dropped below the required level.. It appears on 2 Keston models in our database.
Technical description: Low system water pressure
DIY fix possible
Locate the filling loop, which is a silver braided flexible hose connected between two pipes under your boiler.Open the small valve or tap on the loop to let water flow into the system until the pressure gauge reads between 1.0 and 1.5 bar.Fully close both valves on the loop to stop the water flow and prevent over-pressurisation.
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Keston models that show the Water Pressure fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Keston Water Pressure fault code information on this page is sourced and cross-checked against the official Keston service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026