BoilerFaultCodesVaillant D.47 Fault Code
Also written as D47 — same fault.
The Vaillant D.47 fault code means: your boiler is struggling to read the temperature from the sensor installed outside your home, so it is temporarily using a default setting to ensure your heating still works.. It appears on 19 Vaillant models in our database.
Technical description: Outsidetemperature(withweathercompensator)
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.47 fault code
Click a model for the full fault code list and model-specific repair notes.
- ecoFIT Pure 418 Repair: £90-180
- ecoFIT Pure 425 Repair: £90-180
- ecoFIT Pure 825
- ecoFIT Pure 830 Repair: £120-200
- ecoFIT Pure 835 Repair: £90-180
- ecoMAX Repair: £120-200
- ecoMAX 613 Repair: £100-200
- ecoMAX 618 Repair: £120-200
- ecoMAX 622 Repair: £120-200
- ecoMAX 635 Repair: £120-200
- ecoMAX 824/2 E Repair: £100-200
- ecoMAX 828/2 E Repair: £100-200
- ecoMAX 835 E Repair: £100-200
- Ecomax Condensing 600/800 series Repair: £100-200
- ecoTEC plus VU GB 656/4-5 A Repair: £100-200
- ecoTEC sustain
- Home Combi 25 Repair: £120-200
- Home Combi 30 Repair: £120-200
- Home Combi 35 Repair: £120-200
Source
Vaillant D.47 fault code information on this page is sourced and cross-checked against the official Vaillant service / installation manuals for each affected model.
- Vaillant ecoFIT Pure 425 manual (PDF)
- Vaillant ecoFIT Pure 835 manual (PDF)
- Vaillant Ecomax Condensing 600/800 series manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026