BoilerFaultCodesViessmann 38 Fault Code
The Viessmann 38 fault code means: your boiler has stopped working because it cannot accurately measure its own internal temperature due to a broken or disconnected sensor wire.. It appears on 12 Viessmann models in our database.
Technical description: Burner blocked - Boiler temperature sensor lead break
What causes the Viessmann 38 fault?
This fault occurs when the boiler's main internal thermometer stops sending a steady electrical signal to the control board. The most common reason is a physical break in the thin copper wiring or a connector that has vibrated loose, preventing the boiler from knowing its own temperature. Because the boiler cannot safely monitor if it is overheating, it shuts down the burner as a safety precaution.
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 38 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: £120-220
- Vitodens 100-W Repair: £120-220
- Vitodens 100-W WB1A Repair: £120-220
- Vitodens 100-W WB1B Repair: £150-250
- Vitodens 111-W Repair: £150-250
- Vitodens 200-W Repair: £120-220
- Vitodens 222-F Repair: £120-220
- Vitodens 242-F B2UA Repair: £120-£200
- Vitodens 242-F FB2B Repair: £120-220
- Vitodens 300-W Repair: £120-£210
- Vitodens 333-F Repair: £120-220
Source
Viessmann 38 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