HVACopediaViessmann · Boiler
F.57 Room temperature sensor open circuit
What the control is telling you
Normal operation but without room temperature influence.
Applies to: Vitodens 200-W B2HE 85, 120, 150, 199
Likely causes
- Open circuit on room sensor
Test and repair steps
- Check the remote control setting in the commissioning assistant.
- Check plug and cable of the external room sensor of the heating circuit.
- If no external room sensor is fitted, replace the Vitotrol programming unit.
Models that show this code
4 models in Vitodens 200-W B2HE
Other codes on the same units
- F.546 HC3 mixed supply sensor open circuit
- F.547 HC3 mixed supply sensor short circuit
- F.548 HC4 mixed supply sensor fault (open circuit)
- F.549 HC4 mixed supply sensor short circuit
- F.574 HC1 room sensor not available
- F.58 Room temperature sensor short circuit
- F.59 Supply voltage too low, burner locked out
- F.62 High limit safety cut-out tripped
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Source: Viessmann Vitodens 200-W B2HE 85/120/150/199 Service Instructions 6167 813-24 (09/2026), Fault messages, p.62-73. Summarized in our own words; check the original manual for your model.
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For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.