BoilerFaultCodesVaillant CONNECTION Fault Code
The Vaillant CONNECTION fault code means: your boiler's main control panel has lost communication with its internal electronic brain, meaning the system cannot receive or process any instructions to work.. It appears on 25 Vaillant models in our database.
Technical description: No communication with the PCB
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 CONNECTION fault code
Click a model for the full fault code list and model-specific repair notes.
- Atmomax Repair: £180-450
- Combi Compact 242EB Repair: £180-450
- Combi Compact 282EB Repair: £180-450
- Combicompact vcw282eh Repair: £180-450
- ecoFIT Pure 435 Repair: £150-300
- ecoFIT pure 612
- ecoFIT pure 615
- ecoFIT pure 618
- ecoFIT pure 630
- ecoFIT Pure 825 Repair: £150-300
- ecoFIT Pure 830 Repair: £180-350
- ecoFIT Pure 835 Repair: £150-300
- ecoFIT sustain 615
- ecoFIT sustain 618
- ecoFIT sustain 630
- ecoFIT sustain 825
- ecoFIT sustain 830
- ecoFIT sustain 835
- ecoTEC plus 412 Repair: £200-450
- ecoTEC plus 415 Repair: £200-450
- ecoTEC plus 418 Repair: £200-450
- ecoTEC plus 424 Repair: £200-450
- ecoTEC plus 430 Repair: £200-450
- ecoTEC Plus 610 Repair: £200-450
- ecoTEC sustain Repair: £150-300
Source
Vaillant CONNECTION fault code information on this page is sourced and cross-checked against the official Vaillant service / installation manuals for each affected model.
- Vaillant Combicompact vcw282eh manual (PDF)
- Vaillant Combi Compact 282EB manual (PDF)
- Vaillant ecoFIT Pure 835 manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026