BoilerFaultCodesThe 4 most common faults
01
E5 High DIY-safe
Your boiler's burner has stopped working and has entered a safety lockout mode, meaning the heating and hot water will not function until it is reset or repaired.
What to try first
Check that there is enough heating oil in your storage tank.Ensure the oil supply valves are fully open.Press the illuminated manual reset button on the burner once (if it fails to start after one try, do not keep pressing it).
02
E1 High Engineer
Your boiler's internal temperature sensor has stopped sending the correct signal, meaning the system doesn't know how hot the water is and has shut down for safety.
Full guide for E103
E2 High Engineer
Your boiler has detected an issue with the sensor that monitors the temperature of the exhaust gases, causing the system to shut down as a safety precaution.
Full guide for E204
E3 High Engineer
Your boiler has detected a problem with the sensor that monitors the temperature of the exhaust gases, causing the system to shut down for safety.
Full guide for E3on the Firebird Popular
PhotocellOil pumpBurner control boxNozzleControl thermistor (NTC sensor)Sensor wiring harness
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 Firebird 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