Viessmann · Selected Vitodens and Vitotronic ranges
F6 / 58 / F9 / F-E1 / F-E2 / F-F6Fan not at standstill or fan plug connection fault
This code applies to Vitodens 100-W, Vitodens 200-W, Vitodens 222-F, Vitotronic 100, Vitotronic 200, Vitotronic 200-H, Vitotronic 300, Vitotronic 300-K, Vitocontrol-S. Fault codes narrow down the likely problem, but they do not replace a model-specific diagnosis.
What you can safely check
- Do not open the case or inspect the fan or flue yourself.
- Arrange a Gas Safe registered engineer.
How an engineer may fix it
Check fan movement and speed feedback, wiring and connectors, air/flue restrictions and the control board; repair or replace the defective part and verify combustion.
Viessmann warns that the same code can have different meanings on different models. The exact manual must take precedence.
Manufacturer source: Viessmann UK — Fault Code Checker. Checked 15 August 2026. The appliance manual and an engineer’s on-site diagnosis take precedence. Never remove the boiler case yourself.