E10 displayed, no communication between display module and main control board

Safety: Unplug the softener before opening the control housing.

• 1. Inspect cable connections: Remove the control cover and locate the ribbon or harness connecting the display/keypad to the main board. Reseat both ends firmly.
• 2. Check for moisture: Look for condensation or water intrusion inside the control housing. Dry thoroughly and correct any leaks from plumbing above the unit.
• 3. Examine cable and keypad: Look for cracks, kinks, or corrosion on the ribbon cable and keypad tail. Replace if damaged.
• 4. Test operation: Restore power and see if the display responds. If E10 persists, either the display module or main board is defective.

Next step: Replace the RainSoft display/keypad module first (often easier and cheaper). If the fault remains, replace the main control board.