HVACopediaViessmann · Boiler
F.59 Supply voltage too low, burner locked out
What the control is telling you
Burner locked out because of low supply voltage.
Applies to: Vitodens 200-W B2HE 85, 120, 150, 199
Likely causes
- Low mains voltage
- Faulty fan unit
Test and repair steps
- Check the mains voltage.
- If voltage is correct and the fault repeats, replace the fan unit.
Models that show this code
4 models in Vitodens 200-W B2HE
Other codes on the same units
- F.549 HC4 mixed supply sensor short circuit
- F.57 Room temperature sensor open circuit
- F.574 HC1 room sensor not available
- F.58 Room temperature sensor short circuit
- F.62 High limit safety cut-out tripped
- F.63 Flue gas temperature limiter tripped
- F.666 DHW preheating sensor TS3 open circuit
- F.667 DHW preheating sensor TS3 short circuit
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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.
Homeowner looking at this code? See what it means for you and when to call a technician.
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.