What does the Viessmann Vitodens 050-W E359 fault code mean?
The E359 fault code indicates an issue with the system expansion vessel, which is responsible for maintaining pressure within the heating system. A faulty expansion vessel can lead to pressure fluctuations and potential system failures.
Common Causes
- Insufficient Pressure: The expansion vessel may not be properly charged, leading to inadequate pressure in the system.
- Bladder Failure: The internal bladder of the expansion vessel may have ruptured, causing it to lose its ability to absorb pressure changes.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer for this issue, as working with the expansion vessel involves handling pressurized systems and may require specific tools and expertise.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for replacing the expansion vessel is around £250 to £350. This includes the cost of the part and labour, as it requires professional installation to ensure safety and compliance with regulations.