Low
D.20 on Vaillant Combi Compact 242EB

Your boiler is notifying you that it has reached the maximum temperature limit set for heating your hot water cylinder.

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

Maximum set value for target cylinder

DIY fix possible

Check the hot water temperature dial on the boiler control panelTurn the dial down slightly if it is set to maximumMonitor the display to see if the status code changes as the water cools

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Related fault codes

D.22View →D.25View →

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