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 11 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
- ecoFIT Pure 418 Repair: £150-300
- ecoFIT Pure 425 Repair: £150-300
- ecoFIT Pure 435 Repair: £150-300
- ecoFIT Pure 825 Repair: £150-300
- ecoFIT Pure 830 Repair: £180-350
- ecoFIT Pure 835 Repair: £150-300
- 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 Combi Compact 242EB manual (PDF)
- Vaillant Combi Compact 282EB manual (PDF)
- Vaillant ecoFIT Pure 835 manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026