BoilerFaultCodesVaillant d.93 Fault Code
Also written as D93 — same fault.
The Vaillant d.93 fault code means: your boiler has lost its identity settings, meaning it has 'forgotten' its specific configuration and cannot operate until these settings are re-entered by a professional.. It appears on 10 Vaillant models in our database.
Technical description: Setting the product code
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.93 fault code
Click a model for the full fault code list and model-specific repair notes.
- Atmomax Repair: £80-160
- ecoFIT Pure 418 Repair: £100-200
- ecoFIT Pure 425 Repair: £100-200
- ecoFIT Pure 435 Repair: £100-200
- ecoFIT Pure 825 Repair: £120-250
- ecoFIT Pure 830 Repair: £100-180
- ecoFIT Pure 835 Repair: £100-200
- ecoTEC 65kW Repair: £120-250
- ecoTEC sustain Repair: £100-£200
- Home Combi Repair: £100-200
Source
Vaillant d.93 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 ecoTEC 65kW manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026