E20
Termet
Power Supply / Low Voltage Fault
Boiler shows E20, no operation, may be accompanied by other error codes or display anomalies.
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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.
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Possible Causes
Supply voltage outside Termet boiler limits, Faulty internal power supply on PCB, Loose mains connections, Neutral-earth reversal or missing earth
How to Fix / Troubleshooting
Safety first: Electrical work must comply with local regulations. Isolate power before opening any covers.
User checks:
- Check that the boiler is connected to a stable power source and that no extension leads are used.
- Reset the boiler after ensuring the mains supply is stable.
Technician checks:
- Measure mains voltage at the boiler terminals.
- Inspect the mains terminal block and internal fuses.
- Check the PCB power supply section for damage.
- Correct any wiring issues and replace the PCB if the internal supply is faulty.
Consider installing surge protection if supply quality is poor.
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Repair Difficulty
Hard
4/5
Required Part
Main Control PCB
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