Medium
F4 on Heatline Solaris

Your boiler is having trouble measuring the temperature of your hot water, which usually means it cannot provide hot water to your taps.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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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

Domestic Hot Water (DHW) sensor fault

Engineer required

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

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Related fault codes

F1View →F3View →

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