What does the Vaillant ecoTEC plus F55 fault code mean?
The F55 fault code on a Vaillant ecoTEC plus boiler indicates a problem with the system flow, which can prevent the boiler from operating efficiently. This issue typically arises due to insufficient water flow through the heating system.
Common Causes
- Blocked Filter: A blockage in the system filter can restrict water flow, leading to the F55 error.
- Pump Failure: If the circulation pump is malfunctioning or has failed, it may not be able to move water effectively through the system.
Can I fix it myself? (DIY)
It is advisable to call a Gas Safe Engineer for this issue, as it may involve complex components and safety risks. Attempting to fix gas or electrical issues without proper training can be dangerous.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for resolving the F55 fault could be around £150 to £300, depending on whether a pump replacement or filter cleaning is necessary. This estimate reflects the cost of parts and labour for a qualified engineer.