Applicable Systems
Vitodens
Symptoms
The controller has detected an internal fault or lost control of a subsystem. System operation may be erratic or halted.
Possible Causes
- Controller firmware corrupted or crashed
- Internal memory or processor fault
- Output driver or relay on the controller board failed
Troubleshooting Steps
- Step 1: Check controller status indicators and error logs
Error log shows specific fault details - Step 2: Attempt controller restart or firmware reload
Controller restarts successfully - Step 3: Inspect controller board for visible damage and replace if necessary
Board intact or replaced
How to Reset
To reset: Reset or power-cycle the controller after addressing the internal fault.
Source: Viessmann Vitodens Boiler Manual, Viessmann Werke GmbH
Category: Home Boiler