Medium
S.85 on Vaillant Combi Compact 242EB

Your boiler is struggling to move enough water through the system to operate safely and effectively.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description

Service message quantity of circulation water

DIY fix possible

Check that all radiator valves are fully openEnsure the boiler pressure gauge is between 1.0 and 1.5 barCheck if any bypass valves in your heating system are closed

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Related fault codes

F.22View →F.24View →S.53View →

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