Low
d.39 on Vaillant Home System

Your boiler is simply displaying the current temperature of the water in your solar heating panels.

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

Water temperature in the solar circuit: Current value

DIY fix possible

This fault may be fixable without an engineer. Check your manual first.

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