BoilerFaultCodesViessmann F.762 Fault Code
Also written as F762 — same fault.
The Viessmann F.762 fault code means: your boiler has stopped working because the water pressure inside your heating system has dropped too low to operate safely.. It appears on 1 Viessmann model in our database.
Technical description: System in a fault state. System pressure too low.
DIY fix possible
Locate the external filling loop, which is a silver braided hose connecting two pipes near the boiler.Slowly open the valve(s) on the loop to allow mains water into the system until the pressure gauge reads between 1.0 and 1.5 bar.Close the valve(s) tightly and check the display to see if the error has cleared.
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Viessmann models that show the F.762 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Viessmann F.762 fault code information on this page is sourced and cross-checked against the official Viessmann service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026