BoilerFaultCodesThe 4 most common faults
01
E5 High DIY-safe
Your boiler's burner has stopped working and locked itself out, meaning the system has shut down to prevent damage or safety issues.
What to try first
Check that you have enough heating oil in your storage tank.Ensure the oil supply valve is fully open.Press the illuminated reset button on the front of the burner once to attempt a restart.
02
E1 High Engineer
Your boiler's internal temperature sensor has stopped sending the correct information to the control board, preventing the system from heating up.
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 for safety.
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 15-20
PhotocellOil pumpControl boxNozzleControl thermistor (NTC 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