BoilerFaultCodesThe 6 most common faults
01
E119 High DIY-safe
Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
What to try first
Locate the external filling loop, which is usually a flexible silver hose connected between two pipes under your boiler.Open the valves on both ends of the filling loop to allow cold mains water into the system until the pressure gauge reads between 1.0 and 1.5 bar.Close both valves tightly to stop the flow of water and check the gauge remains steady.
02
E20 High Engineer
Your boiler has stopped working because it is unable to accurately measure the temperature of the water used for your heating system.
Full guide for E2003
E28 High Engineer
Your boiler has detected an issue with the sensor that monitors the temperature of the gases leaving your flue, causing it to shut down for safety.
Full guide for E2804
E50 High Engineer
Your boiler has lost the ability to accurately measure the temperature of the hot water, so it has shut down to prevent the system from overheating.
Full guide for E5005
E110 High Engineer
Your boiler has switched itself off because it has become dangerously hot and requires a professional to investigate why it is overheating.
Full guide for E11006
E125 High Engineer
Your boiler has detected that water is not moving around your heating system properly, so it has safely shut down to prevent overheating.
Full guide for E125on the Baxi Duo-tec Heat
Water pressure switchPressure relief valvePressure gaugeCentral Heating NTC SensorWiring harnessFlue NTC sensor
Based on parts cited in our fault code database. Your engineer will confirm what's actually needed after diagnosis.
Call a Gas Safe engineer if…
- You can smell gas or see signs of a leak
- The Baxi shows an Emergency or High severity code
- The boiler keeps locking out after repeated resets
- You've tried the DIY checks and the fault hasn't cleared
- There's visible water leaking from the boiler
- The flame is yellow or orange instead of blue