E16 error and the unit indicates drain flow problems during regeneration

Safety first: Place the softener in bypass and disconnect power before removing the drain line. Be prepared for water discharge.

• Inspect drain hose routing: Ensure the Nobel drain hose runs downhill with no sharp bends or kinks. The end of the hose should not be submerged in standing water.
• Check for blockages: Disconnect the hose from the control valve and blow through it or flush with water to confirm it is clear. Remove any debris or scale.
• Clean drain flow control: Many valves include a small drain flow control orifice. Remove it from the drain port and clean any buildup. Do not enlarge the orifice.
• Protect from freezing: In unheated spaces, insulate or reroute the drain line to prevent freezing. Thaw any frozen sections slowly with warm air, not open flame.
• Test regeneration: Reconnect the drain line securely, restore power, and run a manual regeneration. Observe the drain discharge during backwash and rinse stages to ensure strong, steady flow.

If E16 recurs with a clear, properly routed drain, the internal valve passages may be restricted and the control valve may need professional service.