Low
d.08 on Vaillant Home System

This is a normal status code showing whether your external heating controls are currently asking the boiler to provide heat or not.

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

Status of the 230V thermostat: 0=Room thermostat open (no heat requirement), 1=Room thermostat closed (heat requirement)

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

Check if your wall thermostat is turned up high enough to trigger the heatingEnsure the batteries in your wireless thermostat or programmer have not run outCheck that your heating timer is set to an 'On' period

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d.00View →S.31View →

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