Firebird E2 Fault Code
The Firebird E2 fault code means: 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.. It appears on 4 Firebird models in our database.
Technical description: Flue thermistor fault
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Firebird models that show the E2 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Firebird E2 fault code information on this page is sourced and cross-checked against the official Firebird service / installation manuals for each affected model.
- Firebird Envirogreen Regular manual (PDF)
- Firebird Popular manual (PDF)
- Firebird Popular 15-20 manual (PDF)
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026