E9
BWT Power Supply / Low Voltage Fault

Display shows E9 and the unit will not operate, often after a power event

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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

Defective BWT power adapter, Loose low-voltage connector at control board, Household outlet not supplying power, Internal power regulator failure on PCB

How to Fix / Troubleshooting

Safety first: Work with power disconnected. Do not open sealed power adapters.

  • Check outlet: Plug another device into the same outlet to confirm it has power.
  • Inspect adapter: Verify that the BWT-branded power adapter is firmly plugged into both the outlet and the softener. Look for damage to the cable or plug.
  • Measure output (if skilled): Using a multimeter, check the adapter’s DC output matches the rating on its label. Replace if no or low output.
  • Check board connector: Open the control housing and ensure the low-voltage connector from the adapter is fully seated on the PCB.
  • Power reset: After confirming good power, reconnect and see if E9 clears. If not, the internal power circuitry on the control board may be faulty.

Do not attempt board-level repairs unless qualified; replace the BWT control board if necessary.

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Repair Difficulty

Medium 3/5

Required Part

BWT power adapter
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