How to fix Worcester Bosch Greenstar CDi fault code F34

What does the Worcester Bosch Greenstar CDi F34 fault code mean?

The F34 fault code indicates a problem with the ignition lead in the Worcester Bosch Greenstar CDi boiler. This issue can prevent the boiler from igniting, leading to a lack of heating and hot water.

Common Causes

  • Damaged Ignition Lead: The ignition lead may be worn or damaged, preventing it from effectively transferring the spark needed for ignition.
  • Loose Connections: Poor connections at the ignition lead or related components can disrupt the ignition process, causing the fault code to appear.

Can I fix it myself? (DIY)

It is highly recommended to call a Gas Safe Engineer for this issue, as working with gas and electrical components can be dangerous. Attempting to fix ignition-related problems without proper training can lead to further complications.

Estimated Repair Cost (2026 UK Prices)

The estimated repair cost for replacing a faulty ignition lead is around £120. This includes the cost of the part and labour, as ignition leads are relatively inexpensive but require professional installation.