D.047 Low

Vaillant D.047 Fault Code

Also written as D047 — same fault.

The Vaillant D.047 fault code means: your boiler is struggling to read the temperature from the sensor installed outside your home, so it is using a default setting to keep your heating running.. It appears on 7 Vaillant models in our database.

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: Outdoortemperature
Typical repair cost £120-200 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Vaillant models that show the D.047 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Vaillant D.047 fault code information on this page is sourced and cross-checked against the official Vaillant service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026