How to fix Ideal Mini fault code F78

What does the Ideal Mini F78 fault code mean?

The F78 fault code on the Ideal Mini boiler indicates a flow rate fault within the central heating system. This typically suggests that the boiler is not receiving adequate water flow, which can lead to overheating and potential damage.

Common Causes

  • Blocked Filter: A blockage in the system filter can restrict water flow, triggering the F78 fault code.
  • Pump Failure: If the circulation pump is malfunctioning or has failed, it may not be able to maintain the necessary flow rate.

Can I fix it myself? (DIY)

While some issues may be resolved by checking and cleaning the system filter, it is highly recommended to call a Gas Safe Engineer for any gas or electrical-related problems to ensure safety and compliance with regulations.

Estimated Repair Cost (2026 UK Prices)

The estimated repair cost for addressing the F78 fault could range around £150 to £300, depending on whether a filter cleaning or pump replacement is necessary. This estimate reflects the cost of parts and labour for a qualified engineer.