BoilerFaultCodesViessmann I.57 Fault Code
Also written as I57 — same fault.
The Viessmann I.57 fault code means: your boiler has received an external signal to stop running, likely from a smart thermostat, heat pump interface, or safety switch that is temporarily preventing it from firing up.. It appears on 4 Viessmann models in our database.
Technical description: External blocking active
DIY fix possible
Check if your thermostat or heating controller is set too low or has run out of batteries.Ensure any external switches or 'Frost Stat' units haven't been triggered by mistake.Restart the boiler using the power button to see if the external signal clears.
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Viessmann models that show the I.57 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Viessmann I.57 fault code information on this page is sourced and cross-checked against the official Viessmann service / installation manuals for each affected model.
- Viessmann Vitodens 100-W WB1A manual (PDF)
- Viessmann Vitodens 200-W B2HF System manual (PDF)
- Viessmann Vitodens 200-W B2KF Combi manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026