BoilerFaultCodesViessmann 68 Fault Code
The Viessmann 68 fault code means: your boiler has lost communication with a sensor that monitors the water returning to it, which prevents the system from heating your home properly.. It appears on 5 Viessmann models in our database.
Technical description: Return temperature sensor lead break
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Avoid the next call-out bill
A cover plan would handle faults like 68: no call-out fees, no surprise bills.
Affiliate links. We may earn a commission at no extra cost to you.
Viessmann models that show the 68 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Viessmann 68 fault code information on this page is sourced and cross-checked against the official Viessmann service / installation manuals for each affected model.
- Viessmann Vitodens 100 Compact manual (PDF)
- Viessmann Vitodens 100-W B1GA manual →
- Viessmann Vitodens 111-W B1LF 32kW manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026