Low
D.77 on Vaillant Combi Compact 242EB

Your boiler is limiting the amount of power it uses to heat your hot water, likely due to a sensor detecting that heat isn't being transferred quickly enough.

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.78View →F.22View →F.24View →

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