E09
Cillit
Backup Power / Battery Fault
E09 displayed, unit does not keep correct time or loses settings
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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
Failed backup battery on Cillit control board, Loose battery holder, Aged coin cell, Faulty charging circuit (if rechargeable)
How to Fix / Troubleshooting
Safety: Disconnect mains power before touching the control electronics.
- Locate backup battery: Remove the control panel cover and identify the small coin cell or battery pack on the Cillit PCB.
- Inspect and reseat: Check for corrosion on the battery contacts. Clean gently with a dry cloth and reseat the battery firmly in its holder.
- Measure voltage: Use a multimeter to measure the battery voltage. If it is significantly below its rated value (e.g. <2.7 V for a 3 V coin cell), replace it with the same type recommended by Cillit.
- Reprogram settings: After replacing the battery, re‑enter time, date, hardness, and regeneration parameters according to the user manual.
- Board replacement: If the new battery discharges quickly or the board does not recognize it, the charging/backup circuit on the Cillit main control PCB may be defective and the board should be replaced.
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Repair Difficulty
Medium
3/5
Required Part
Cillit control board backup battery
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