BoilerFaultCodesVaillant d.58 Fault Code
Also written as D58 — same fault.
The Vaillant d.58 fault code means: your boiler is currently communicating with an optional solar water heating system to check if it can help warm your water, which is a normal operational status rather than a fault.. It appears on 17 Vaillant models in our database.
Technical description: Solar circuit reheating function
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.58 fault code
Click a model for the full fault code list and model-specific repair notes.
- Atmomax
- ecoFIT Pure 418
- ecoFIT Pure 425 Repair: £0-80
- ecoFIT Pure 435 Repair: £0-120
- ecoFIT Pure 825
- ecoFIT Pure 830
- ecoFIT Pure 835
- ecoTEC Plus 615
- ecoTEC Plus 620
- ecoTEC Plus 625
- ecoTEC Plus 630
- ecoTEC Plus 635
- ecoTEC Plus 840
- ecoTEC Pro / ecoTEC Plus
- ecoTEC sustain
- Home Combi
- Home System Repair: £0-80
Source
Vaillant d.58 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 835 manual (PDF)
- Vaillant ecoTEC Plus 840 manual (PDF)
- Vaillant ecoTEC Pro / ecoTEC Plus manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026