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, usually found underneath the boiler.Open the valves to allow mains water to enter the system until the pressure gauge on the front reads between 1.0 and 1.5 bar.Ensure both valves are tightened firmly back to the closed position.
02
E20 High Engineer
Your boiler's temperature sensor is failing to provide accurate readings, which has caused the system to stop heating your home as a safety precaution.
Full guide for E2003
E28 High Engineer
Your boiler has detected a faulty sensor in the flue system, meaning it cannot reliably monitor exhaust temperatures and has stopped working for your safety.
Full guide for E2804
E50 High Engineer
Your boiler is struggling to accurately measure the temperature of the hot water it produces, so it has shut down to prevent the system from overheating.
Full guide for E5005
E110 High Engineer
Your boiler has detected that it is getting too hot and has automatically shut itself down to prevent damage.
Full guide for E11006
E125 High Engineer
Your boiler is struggling to pump water around your heating system correctly, usually because the water pressure is too low or the pump is blocked.
Full guide for E125on the Baxi Duo-tec Combi HE
Pressure relief valvePressure sensorCentral Heating NTC SensorFlue NTC SensorWiring harnessDomestic Hot Water (DHW) NTC thermistor
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