Medium
D.36 on Vaillant Combi Compact 242EB

Your boiler is struggling to detect when you turn on a hot tap, meaning your water might stay cold or fluctuate in temperature.

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

Hot water flow sensor

Engineer required

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

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Related fault codes

D.35View →F.22View →

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