Display shows “Err 16” and the unit reports a communication error between modules.

Safety first: Unplug the unit before removing any covers or boards.

Steps to correct:

• 1. Reseat interconnect cables: If your EcoWater model has separate display and main boards, unplug and firmly reseat the communication cable between them.
• 2. Inspect for damage: Look for pinched or cut cables, burnt components, or corrosion on connectors.
• 3. Reduce interference: Ensure that high-current devices (well pumps, large motors) are not sharing the same outlet or running cables parallel to the softener’s low-voltage wiring.
• 4. Verify board compatibility: If a board was recently replaced, confirm that its part number matches the original and is approved for your EcoWater model.
• 5. Replace faulty board: If Err 16 persists, replace the EcoWater main control board or display board as indicated by diagnostic procedures.