BoilerFaultCodesHeatline 0.8bar Fault Code
Also written as 08BAR — same fault.
The Heatline 0.8bar fault code means: your boiler has detected that the water pressure in your heating system has fallen too low for it to operate safely, so it has paused its functions to protect itself.. It appears on 2 Heatline models in our database.
Technical description: LCD display will flash should the pressure drop below 0.8bar
DIY fix possible
Locate the filling loop, which is usually a flexible silver hose under the boiler connecting two pipes.Open the valves at both ends of the filling loop to allow water to enter the system while watching the pressure gauge.Close both valves firmly once the needle reaches the green zone between 1.0 and 1.5 bar.
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Gas Safe Register →Heatline models that show the 0.8bar fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Heatline 0.8bar 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