How to fix Baxi Duo-tec fault code F22

What does the Baxi Duo-tec F22 fault code mean?

The F22 fault code on a Baxi Duo-tec boiler indicates a dry fire condition or low water pressure. This typically means that the boiler is unable to detect sufficient water in the system to operate safely.

Common Causes

  • Low Water Pressure: This can occur due to leaks in the system or insufficient water being added to the boiler.
  • Faulty Pressure Sensor: A malfunctioning pressure sensor may incorrectly signal low pressure, leading to the F22 fault code.

Can I fix it myself? (DIY)

You can check and refill the boiler’s pressure by locating the filling loop and adding water until the pressure gauge reads between 1-1.5 bar. If the issue persists or if you suspect a leak, it is advisable to call a Gas Safe Engineer.

Estimated Repair Cost (2026 UK Prices)

The estimated repair cost for addressing the F22 fault could range from £100 to £200, primarily for pressure sensor replacement or system refill, depending on the specific issue and parts required.