E20
Hewalex
General Safety Circuit Open (Emergency Stop / Door Switch / Flow Chain)
Display shows E20; heater does not start and may indicate safety chain open.
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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
Open safety interlock (service switch, door switch), Tripped external safety thermostat, Broken wire in safety loop, Faulty safety relay on PCB
How to Fix / Troubleshooting
Safety first: Confirm that no safety device has been intentionally activated before attempting reset.
- Check service switches: Ensure any external emergency stop or service switches in the heater circuit are in the ON position.
- Inspect access panels: Some models have door interlock switches; confirm panels are correctly closed and latched.
- Trace safety loop: Visually inspect wiring in the safety chain for disconnections or damage.
- Reset external devices: If an external high‑limit thermostat or flow switch has tripped, correct the underlying cause and reset it according to manufacturer instructions.
- Professional diagnosis: If all devices appear normal, a technician should test continuity of the safety loop and the safety relay on the PCB.
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Repair Difficulty
Hard
4/5
Required Part
Safety Interlock Circuit
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