Complete guide to Vitodens 050-W, 100-W, 111-W, 200-W series fault codes with troubleshooting advice
Viessmann boilers display error codes with a letter prefix followed by numbers. Here is the complete list:
| Code | Meaning | Quick Fix | DIY? |
|---|---|---|---|
| 0C | Burner control unit fault | Reset boiler by pressing the reset button | No |
| 0F | Maintenance required | Schedule annual service | No |
| A0 | Combustion fault - flame signal issue | Reset boiler, check gas supply | No |
| B0 | External control fault | Check external controls and wiring | No |
| C0 | Flue gas temperature sensor fault | Reset boiler | No |
| E0 | Boiler temperature sensor fault | Reset boiler | No |
| F0 | DHW temperature sensor fault | Reset boiler | No |
| F2 | Low water pressure | Top up pressure using filling loop to 1.0-1.5 bar | Yes |
| F3 | Flame lost during operation | Check gas supply, thaw frozen condensate in winter | Partial |
| F4 | No ignition - burner didn't light | Check gas supply, reset boiler, thaw condensate pipe | Partial |
| F5 | Safety temperature limiter activated | Let boiler cool, check pump operation, bleed radiators | Partial |
| F6 | Flame detection fault | Do NOT repeatedly reset - call engineer | No |
| F30 | Short circuit - boiler sensor | Reset boiler | No |
| F38 | Open circuit - boiler sensor | Reset boiler | No |
| F50 | DHW sensor short circuit | Reset boiler | No |
| F51 | DHW sensor open circuit | Reset boiler | No |
| F83 | Flow/return temperature difference too high | Check system circulation, bleed radiators | Partial |
| F84 | Flow/return sensor difference fault | Reset boiler | No |
| F85 | Flow sensor wrong position | Reset boiler | No |
| F86 | Return sensor wrong position | Reset boiler | No |
Our Gas Safe engineers service all Viessmann models across Harrow and London.