E20
Grünbeck
Twin Column Synchronization / Communication Fault
Display shows E20 and the unit indicates a dual-column synchronization error (twin system)
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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
Communication cable between columns disconnected, One valve head without power, Column position mismatch, Defective twin control module
How to Fix / Troubleshooting
Safety: Disconnect power to both columns before working on wiring.
- Check power to both heads: Ensure both valve heads of the Grünbeck twin softener receive power and show a display.
- Inspect communication link: Verify that the interconnecting communication cable between the two heads is firmly plugged in at both ends and not damaged.
- Synchronize positions: Manually set both columns to the service position according to the service manual, then restart the system so the controller can resynchronize.
- Test regeneration: Trigger a manual regeneration on one column and confirm that the other column remains in service. If synchronization fails again, the twin control module or one valve head PCB may be defective.
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Repair Difficulty
Hard
4/5
Required Part
Twin System Communication Cable and Control Module
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