BoilerFaultCodesViessmann 10 Fault Code
The Viessmann 10 fault code means: your boiler's outside thermometer has developed a fault, causing the system to 'think' it is 0°c outside and adjust your heating accordingly.. It appears on 12 Viessmann models in our database.
Technical description: Controls according to 0°C outside temperature - Outside temperature sensor shorted out
What causes the Viessmann 10 fault?
This fault occurs when the electrical connection to the external temperature probe is broken or short-circuited. The most common reasons are moisture getting into the sensor housing, damage to the cable running along the outside wall, or the internal component simply failing over time.
This fault is often noticed during autumn or early winter when temperature changes first trigger the boiler to look for external data to adjust the heating.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Viessmann models that show the 10 fault code
Click a model for the full fault code list and model-specific repair notes.
- Vitodens 050-W Repair: £120-220
- Vitodens 050-W BPJD Repair: £120-200
- Vitodens 100-W Repair: £120-200
- Vitodens 100-W WB1A Repair: £120-200
- Vitodens 100-W WB1B Repair: £120-200
- Vitodens 111-W Repair: £120-200
- Vitodens 200-W Repair: £120-220
- Vitodens 222-F Repair: £120-220
- Vitodens 242-F B2UA Repair: £120-£210
- Vitodens 242-F FB2B Repair: £90-160
- Vitodens 300-W Repair: £120-£200
- Vitodens 333-F Repair: £90-180
Source
Viessmann 10 fault code information on this page is sourced and cross-checked against the official Viessmann service / installation manuals for each affected model.
- Viessmann Vitodens 050-W BPJD manual (PDF)
- Viessmann Vitodens 100-W manual (PDF)
- Viessmann Vitodens 100-W WB1A manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026