BoilerFaultCodesHeatline F06 Fault Code
The Heatline F06 fault code means: your boiler has stopped working because the amount of water inside your heating system is too low to run safely.. It appears on 2 Heatline models in our database.
Technical description: System water pressure low
DIY fix possible
Locate the external filling loop (a flexible silver hose) underneath the boiler.Open the valves at both ends of the hose to slowly let water into the system.Monitor the pressure gauge on the front of the boiler until the needle reaches 1.5 bar.Close both valves firmly and ensure the hose is disconnected if required.
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Gas Safe Register →Heatline models that show the F06 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Heatline F06 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 27 April 2026