BoilerFaultCodesHeatline F0 Fault Code
The Heatline F0 fault code means: your boiler has detected that there is not enough water pressure in the system to operate safely, which has caused it to shut down.. It appears on 3 Heatline models in our database.
Technical description: Low Water Pressure Error
DIY fix possible
Locate the filling loop (the silver flexible hose) underneath your boiler.Open the two valves slowly to allow water into the system.Watch the pressure gauge and close the valves once it reaches between 1.0 and 1.5 bar.
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Heatline models that show the F0 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Heatline F0 fault code information on this page is sourced and cross-checked against the official Heatline service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026