Low
d.8 on Vaillant ecoMAX System 612

Your boiler is receiving a signal from your room thermostat or programmer asking for the heating or hot water to turn on.

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

External controls heat demand

From this model's manual
Verified against the Vaillant Ecomax 613 installation & service manual, page 47.
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

Check your room thermostat or programmer to see if it is currently calling for heatAdjust the thermostat temperature settings to see if the display code changesIf the boiler is operating normally, this is a status indicator rather than an actual fault

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d.0View →d.1View →

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