E12
Hewalex
Phase / Power Supply Error (for 3‑phase models)
Display shows E12; unit may start but quickly stops with alarm.
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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
Incorrect phase sequence, Missing phase (single-phasing), Loose terminal connections, Undervoltage or overvoltage on supply lines
How to Fix / Troubleshooting
Safety first: Only qualified personnel should work on 3‑phase electrical connections. Turn off and lock out the main breaker.
- Verify wiring: Compare the supply wiring to the Hewalex installation diagram. Ensure L1, L2, and L3 are correctly connected and neutral/earth are properly terminated.
- Tighten terminals: Check that all terminal screws on the main contactor and terminal block are tight.
- Measure voltages: Using a multimeter, verify that all three phases are present and within the voltage range specified on the nameplate.
- Correct phase rotation: If the unit indicates phase sequence error, swap any two phases to correct rotation (by a qualified electrician).
- Restart: Restore power and clear the error. If E12 persists, the phase monitor circuit on the PCB may be faulty.
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Repair Difficulty
Professional Required
5/5
Required Part
Phase Monitoring Circuit / Main Terminal Block
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