Medium
F.81 on Vaillant ecoTEC exclusive

Your boiler is struggling to heat your hot water tank effectively, causing it to time out before the water reaches the requested temperature.

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

Fault:cylinderchargingpump OnlyinconjunctionwithF.91 Cylinderisnotfullychargedafterspecifiedtime. – Checkcylinderchargingsensorandcylindersensor – AirintheactoSTORpump – Inspectcableharnessforpump – Checktheimpellersensorand/orlimiterintheproduct – Prioritisingdivertervalvedefective – Secondaryheatexchangerblocked – Pumpdefective

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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