How to Fix / Troubleshooting

Safety first: Verify the outlet is safe and not overloaded. Disconnect the softener before inspection.

Check outlet: Plug another device into the same outlet to confirm power is present.
Inspect adapter: Examine the Viessmann power adapter for damage or overheating. Replace with an original-rated adapter if suspect.
Check connectors: Ensure the low-voltage plug is firmly connected to the control board.
Internal fuse: If accessible and permitted by the manual, check any internal fuse on the control board and replace with the same rating if blown.
Board replacement: If the unit remains dead with a known-good adapter, replace the Viessmann control board.

Softener will not power on; display is blank

Possible Causes