What does the Ideal Mini F99 fault code mean?
The F99 fault code on the Ideal Mini indicates a pressure differential fault within the domestic hot water (DHW) system. This typically suggests that there is an issue with the pressure sensing or flow within the system, which can affect the boiler’s ability to provide hot water efficiently.
Common Causes
- Blocked DHW Flow Sensor: A blockage in the flow sensor can prevent accurate pressure readings, leading to the F99 fault code.
- Low System Pressure: Insufficient water pressure in the system can trigger this fault, often due to leaks or insufficient filling.
Can I fix it myself? (DIY)
While some basic checks can be performed, such as ensuring the system pressure is within the recommended range (typically 1-1.5 bar), it is advisable to call a Gas Safe Engineer for any repairs or adjustments related to gas or electrical components.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for addressing the F99 fault could range from £150 to £250, primarily depending on whether the flow sensor needs cleaning or replacement. This cost reflects the typical labour and parts required for such repairs.