What does the Ideal Logic Max F91 fault code mean?
The F91 fault code indicates a calibration mismatch with the domestic hot water (DHW) temperature sensor in the Ideal Logic Max boiler. This means that the temperature readings from the sensor do not align with the expected values, potentially affecting hot water delivery.
Common Causes
- Faulty DHW Temperature Sensor: The sensor may be malfunctioning or damaged, leading to incorrect temperature readings.
- Wiring Issues: Damaged or loose wiring connections to the temperature sensor can cause communication problems, resulting in a calibration mismatch.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer to address this issue, as it involves gas and electrical components that require professional expertise. Attempting to fix it yourself could pose safety risks.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for replacing the DHW temperature sensor is around £120. This includes the cost of the part and labour, as sensor replacement typically requires professional installation.