Firebird Enviro Fault codes & diagnostics

4 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.

System Oil 20-26 kW 2013-present

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Just want the most common Firebird Enviro faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 4 documented codes

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E1

Your boiler's internal temperature sensor has stopped sending the correct information, preventing the system from running safely.

High Engineer only £90-180

Parts commonly replaced

  • NTC Temperature Sensor
  • Wiring Harness
  • Control Board

Related codes

Full explanation for E1
E2

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.

High Engineer only £120-220

Parts commonly replaced

  • Flue gas thermistor
  • Wiring harness
  • Main control board

Related codes

Full explanation for E2
E3

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.

High Engineer only £120-£220

Parts commonly replaced

  • Flue gas thermistor
  • Wiring harness
  • Main PCB

Related codes

Full explanation for E3
E5

Your boiler's burner has stopped working and has gone into a safety lockout mode.

High DIY-safe £120-350

What to check first

  1. Check that you have fuel in your oil tank
  2. Ensure the oil supply valves are fully open
  3. Press the illuminated reset button on the burner once and wait for it to restart

Parts commonly replaced

  • Oil nozzle
  • Photocell
  • Oil pump
  • Control box

Related codes

Full explanation for E5