Low
D.77 on Vaillant Atmomax

Your boiler is currently limiting the amount of energy it uses to heat your hot water cylinder, which may result in your water taking longer to warm up.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description

Limitation of cylinder charging in output in kW

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.22View →F.22View →F.24View →

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