E17 displayed and the unit reports communication error with external accessories (e.g., remote display or leak sensor).

Safety: Disconnect power before plugging or unplugging accessory modules.

• Check connections: Inspect the communication cable between the Hansgrohe softener and any external modules (remote display, leak detector). Ensure plugs are fully seated.
• Inspect cable: Look for cuts, abrasions, or crushed sections. Replace damaged cables.
• Remove accessories: Temporarily disconnect all accessories and power up the softener alone. If E17 clears, reconnect accessories one at a time to identify the faulty module.
• Port inspection: Examine the control board communication port for bent pins or corrosion. Clean gently if needed.
• Replace faulty module: If a specific accessory triggers E17 when connected, replace that module.