Low
d.58 on Vaillant Home System

This is a configuration setting for your solar water heating system that controls whether your boiler automatically heats your water to a high temperature to kill bacteria.

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.

What the manual says

Manufacturer manual

Solar circuit reheating: 0=Boiler's Legionella protection function deactivated, 3=Hot water activated (min. target value 60°C)

From this model's manual
Verified against the Vaillant Home System installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

DIY fix possible

Identify if you have a solar thermal system connected to your boiler.Access the installer level menu (requires technical manual knowledge).Adjust the d.58 setting to '3' if you want the anti-legionella high-temperature cycle active, or '0' to disable it.

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