Viessmann Vitodens 100-W fault 416
Flue gas temperature sensor placement fault during commissioning
Gas boilerWhat it means
During commissioning, the control unit checks for correct placement of the flue gas temperature sensor. If the sensor is not correctly installed or detected, fault message 416 is displayed.
Likely causes
- Flue gas temperature sensor not correctly installed (bayonet fitting not properly engaged)
- Leaks on the flue gas side
- Flue gas temperature sensor incorrectly positioned
- Incorrect position of the flue gas temperature sensor
- Faulty flue gas temperature sensor
- Air in the gas line causing burner faults during initial commissioning
Where to start
- Observe display during commissioning: 'Fst' appears when flue temperature sensor test is launched, 'Err' shown during test
- If fault message 416 appears, check flue gas temperature sensor position in the flue gas connection
- Check for leaks on the flue gas side
The full answer, free
- 8 more checks in order
- The readings and component tests from the manual
- How to put it right, step by step
- The manual page for this fault (page 95), right under the answer
Safety: Isolate gas and power before you open the case. If you have been into the gas side, do a tightness test, and a combustion and flue check before you hand back. Gas Safe (UK) or RGI (Ireland) work only.
From the Viessmann manual for the Vitodens 100-W. Check the model on the data plate before you order parts.
Other Viessmann Vitodens 100-W fault codes
- 694Burner in a fault state, signal comparison deviation, flue gas high limit safety cut-out
- 799No DHW heating, no central heating, central heating circuit pump electrical fault
- 980No DHW heating (minimum system pressure too low before start)
- 981No DHW heating (minimum system pressure too low during DHW heating)