BoilerFaultCodesIdeal LOW WATER SWITCH Fault Code
Also written as LOWWATERSWITCH — same fault.
The Ideal LOW WATER SWITCH fault code means: your boiler has stopped working because the water pressure inside the heating system has dropped too low.. It appears on 1 Ideal model in our database.
Technical description: System pressure below 1 bar; check system pressure gauge and water pressure switch continuity.
DIY fix possible
Locate the filling loop (usually a silver braided hose with valves beneath the boiler).Open the valves slowly to allow mains water into the system until the gauge reads between 1.0 and 1.5 bar.Close the valves tightly and restart the boiler.
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Ideal models that show the LOW WATER SWITCH fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal LOW WATER SWITCH fault code information on this page is sourced and cross-checked against the official Ideal service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026