How to fix Worcester Bosch Greenstar i fault code F45

What does the Worcester Bosch Greenstar i F45 fault code mean?

The F45 fault code indicates a problem with the expansion vessel in the Worcester Bosch Greenstar i boiler. This typically means that the vessel is either faulty or has lost its charge, affecting the boiler’s ability to maintain pressure.

Common Causes

  • Loss of Pressure: The expansion vessel may have lost its pre-charge pressure, leading to insufficient pressure in the system.
  • Physical Damage: The expansion vessel could be damaged or corroded, causing it to fail and trigger the fault code.

Can I fix it myself? (DIY)

It is not recommended to attempt repairs on the expansion vessel yourself, as this involves handling pressurised systems. It is best to call a qualified Gas Safe Engineer to diagnose and fix the issue safely.

Estimated Repair Cost (2026 UK Prices)

The estimated repair cost for replacing the expansion vessel is around £150 to £250. This includes the cost of the part and labour, as it requires professional installation to ensure safety and compliance with regulations.