HVACopediaViessmann · Boiler
F.468 Ionization current too high during calibration
What the control is telling you
Burner in a fault state.
Applies to: Vitodens 200-W B2HE 85, 120, 150, 199
Likely causes
- Electrode gap
- Dusty air
Test and repair steps
- Check gap between ionization electrode and flame body.
- Check for dust in ventilation air.
- Deposits on electrodes indicate foreign substances in the air.
- If flame body and electrode were replaced, also clean fan unit, gas/air channel and Venturi extension.
- Reset the appliance.
Models that show this code
4 models in Vitodens 200-W B2HE
Other codes on the same units
- F.458 Reset sequence fault
- F.463 Contaminated combustion air / flue recirculation
- F.464 Ionization current too low during calibration
- F.467 Gas supply insufficient during calibration
- F.471 Sensor circuit fault (call for heat)
- F.473 HMU communication error
- F.474 Program run monitoring error
- F.477 Solar differential temperature monitoring
Save it for the next call
Star this code in the HVACopedia app and keep the whole library on your phone for jobs with no signal.
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.