Boiler displays E17, power supply fault or incorrect mains voltage detected.
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Possible Causes
How to Fix / Troubleshooting
Safety first: Only qualified electricians should work on mains wiring. Isolate power at the breaker before opening the boiler.
- Check supply voltage: Measure the mains voltage at the boiler terminals and confirm it matches the rating on the boiler data plate (e.g. 230 V ±10%).
- Inspect terminals: Tighten all live, neutral, and earth connections. Look for signs of overheating or discoloration.
- Verify polarity and earth: Ensure live and neutral are correctly connected and that a solid earth connection is present.
- Surge protection: If the site has unstable power, consider installing surge protection or a stabiliser.
When to call a professional: If the internal power supply on the control board is faulty, the board must be replaced by a technician.
Repair Difficulty
Required Part
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