Brine tank remains dry; no water in bottom even after refill stage

Safety first: Disconnect power and close inlet valve before opening the brine system.

• Check programming: Some systems can operate with a dry brine tank until refill. Confirm whether your Viessmann model is set to this mode.
• Inspect float: Ensure the float is not stuck in the up (closed) position. Clean and free it if necessary.
• Clean refill port: Remove the brine line at the valve head and check the refill port for blockage. Clean as needed.
• Test refill: Manually initiate a regeneration and observe whether water flows into the brine tank during the refill stage. If not, the brine valve may need replacement.