E12
BWT Communication Error Between Display Panel and Main Control Board

Heater display shows E12; unit may run pump but not heat

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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

Loose communication cable between user interface and main PCB, Damaged communication harness, Moisture ingress in control panel, Faulty display board or main PCB

How to Fix / Troubleshooting

Safety first: Turn off power at the breaker before opening any electrical covers.

  • Inspect communication cable: Locate the low-voltage cable connecting the front display panel to the main control board. Check for pinched, cut, or chewed sections.
  • Reseat connectors: Unplug the cable at both ends, inspect for bent pins or corrosion, then reconnect firmly.
  • Dry moisture: If condensation or water is present inside the display housing, dry it thoroughly and identify the source of ingress. Seal any gaps as appropriate.
  • Power reset: Leave power off for 5–10 minutes, then restore and check if E12 clears.

If E12 persists, either the display board or main control board may be defective. A technician can swap-test or measure communication signals to identify the faulty component.

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Repair Difficulty

Hard 4/5

Required Part

BWT User Interface / Display Board
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