BoilerFaultCodesViessmann F1 Fault Code
The Viessmann F1 fault code means: your boiler has shut down because it detected that the exhaust gases have become too hot, which is a safety feature to prevent damage or dangerous operation.. It appears on 9 Viessmann models in our database.
Technical description: Burner in fault state - Flue gas temperature limiter has responded
What causes the Viessmann F1 fault?
This fault occurs when the internal safety sensors detect that the exhaust gases leaving the unit are exceeding safe temperature limits, triggering an immediate shutdown to protect the internal components. The most common reasons are a build-up of limescale or debris inside the heat exchanger that prevents heat from being transferred to the water, or a fault with the temperature sensor itself. It can also be caused by the burner not firing correctly, leading to excessive heat buildup within the casing.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Viessmann models that show the F1 fault code
Click a model for the full fault code list and model-specific repair notes.
- Vitodens 050-W Repair: £100-350
- Vitodens 050-W BPJD Repair: £150-300
- Vitodens 100-W WB1A Repair: £150-300
- Vitodens 100-W WB1B Repair: £250-450
- Vitodens 111-W Repair: £150-350
- Vitodens 222-F Repair: £100-350
- Vitodens 242-F B2UA Repair: £150-300
- Vitodens 242-F FB2B Repair: £150-300
- Vitodens 333-F Repair: £120-350
Source
Viessmann F1 fault code information on this page is sourced and cross-checked against the official Viessmann service / installation manuals for each affected model.
- Viessmann Vitodens 050-W BPJD manual (PDF)
- Viessmann Vitodens 100-W WB1A manual (PDF)
- Viessmann Vitodens 100-W WB1B manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026