What does the Worcester Bosch Greenstar CDi F35 fault code mean?
The F35 fault code indicates a problem with the air pressure switch, which is responsible for detecting whether the boiler is receiving adequate airflow. This issue can prevent the boiler from operating safely and efficiently.
Common Causes
- Blocked Flue: A blockage in the flue can restrict airflow, causing the air pressure switch to fail.
- Faulty Air Pressure Switch: The switch itself may be defective or malfunctioning, leading to incorrect readings.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer for this issue, as it involves gas and electrical components that can be dangerous if handled improperly. Attempting to fix it yourself may void warranties or lead to further complications.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for replacing a faulty air pressure switch on a Worcester Bosch Greenstar CDi is around £150 to £200. This includes the cost of the part and labour, reflecting the complexity of the repair and the need for a qualified technician.