Firebird Envirogreen Fault codes & diagnostics

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

Oil Oil 12-73 kW 2024-present

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Severity at a glance

Each cell = one fault code. Hover to identify.
7 High
Just want the most common Firebird Envirogreen faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 7 documented codes

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Burner lockout

Your boiler has stopped running as a safety precaution because it couldn't successfully light or maintain a flame.

High DIY-safe £120-280

What to check first

  1. Check that you have enough heating oil in your tank.
  2. Ensure the oil supply valve is fully open.
  3. Press the illuminated reset button on the burner control box once.

Parts commonly replaced

  • Oil nozzle
  • Photocell
  • Oil pump
  • Flexible fuel hose
Full explanation for Burner lockout
e1

Your boiler's internal temperature sensor is reporting an error, which means the system cannot monitor its own heat levels and has shut down as a precaution.

High Engineer only £90-180

Parts commonly replaced

  • Flow Thermistor
  • Return Thermistor
  • Wiring Harness

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-£200

Parts commonly replaced

  • Flue thermistor
  • Wiring harness
  • Control board

Related codes

Full explanation for e2
e5

Your boiler's burner has shut itself down for safety and requires a manual restart to try and restore heating and hot water.

High DIY-safe £100-250

What to check first

  1. Locate the red reset button on the burner itself (behind the front casing)
  2. Press the reset button once to see if the burner fires up
  3. Check that you have enough oil in your storage tank

Parts commonly replaced

  • Photocell
  • Oil nozzle
  • Oil pump
  • Control box
Full explanation for e5
High limit

Your boiler has reached an unsafe temperature and has automatically shut down to prevent damage.

High DIY-safe £90-250

What to check first

  1. Wait for the boiler to cool down completely (at least 20-30 minutes).
  2. Ensure all radiator valves are fully open and there are no blockages in the system.
  3. Locate the manual reset button (usually under a black screw cap) and press it firmly.

Parts commonly replaced

  • High limit thermostat
  • Circulation pump
  • Temperature thermistor
Full explanation for High limit
L2

Your boiler has stopped running because it has locked itself out, usually because it can't draw enough oil or light the flame.

High DIY-safe £120-280

What to check first

  1. Check that you have enough oil in your storage tank
  2. Ensure the oil supply valve is fully open
  3. Press the illuminated reset button on the burner once

Parts commonly replaced

  • Oil nozzle
  • Photocell
  • Fuel pump
  • Oil filter
Full explanation for L2
Pump over run thermostat 87˚C

Your boiler has reached a high temperature because the pump stopped spinning prematurely, preventing the system from cooling down properly.

High Engineer only £120-250

Parts commonly replaced

  • Circulating Pump
  • Overheat Thermostat
  • Wiring Loom
Full explanation for Pump over run thermostat 87˚C