How to fix Baxi 600 Series fault code E500

What does the Baxi 600 Series E500 fault code mean?

The E500 fault code on the Baxi 600 Series indicates a lockout condition in the domestic hot water (DHW) system. This typically occurs when the boiler detects a fault that prevents it from safely providing hot water.

Common Causes

  • Blocked DHW Heat Exchanger: A blockage can prevent the flow of water, leading to overheating and triggering a lockout.
  • Faulty DHW Sensor: If the temperature sensor is malfunctioning, it may incorrectly signal the boiler to shut down.

Can I fix it myself? (DIY)

It is recommended to call a Gas Safe Engineer for any gas or electrical issues. However, you can check the pressure gauge and ensure it is within the normal range (1-1.5 bar) and reset the boiler if necessary.

Estimated Repair Cost (2026 UK Prices)

The estimated repair cost for resolving the E500 fault could range from £150 to £300, depending on whether a sensor replacement or heat exchanger cleaning is required. This estimate includes parts and labour.