Firebird Enviro Fault codes & diagnostics

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

System Oil 20-26 kW 2013-present
Download the Firebird Enviro manual The official installation & service manual (PDF) — the exact document these fault codes were verified against. PDF

This boiler uses LED flash patterns

Count the flashes in one repeating group before the pause. That number is your fault code. Do not reset until you have noted it. How to read fault codes →

Severity at a glance

Each cell = one fault code. Hover to identify.
6 High
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 6 documented codes

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LED / flash-pattern codes
Digital codes
Burner control box lockout light lit

Your boiler's burner has shut itself down for safety because it failed to light or stay lit.

High DIY-safe £100-280

What to check first

  1. Check your oil tank level to ensure you haven't run out of fuel.
  2. Ensure the oil supply valve is fully open.
  3. Press the illuminated reset button on the burner once (do not press it more than twice).

Parts commonly replaced

  • Burner nozzle
  • Photocell
  • Oil pump
  • Control box

Related codes

Full explanation for Burner control box lockout light lit
Combi panel red Lockout LED

Your boiler's burner has stopped working, meaning it cannot light the fuel to provide heating or hot water.

High DIY-safe £120-280

What to check first

  1. Check that you have enough heating oil in your storage tank
  2. Ensure the oil supply valve is fully open
  3. Press the red illuminated reset button on the burner once and wait for it to restart

Parts commonly replaced

  • Oil nozzle
  • Fuel pump
  • Photocell
  • Ignition transformer

Related codes

Full explanation for Combi panel red Lockout LED
Combi panel yellow High Limit LED

Your boiler has switched itself off because the water inside became too hot, triggered by a safety sensor to protect the system.

High DIY-safe £90-180

What to check first

  1. Wait for the boiler to cool down completely (at least 20-30 minutes).
  2. Locate the manual reset button for the high-limit thermostat, usually found under a small black screw cap on the control panel.
  3. Unscrew the cap and press the reset button firmly; you should hear a click.
  4. Restart the boiler and check that your radiator valves are open and the system pressure is between 1 and 1.5 bar.

Parts commonly replaced

  • High-limit thermostat
  • Circulation pump
  • Overheat sensor

Related codes

Full explanation for Combi panel yellow High Limit LED
E1

Your boiler's internal temperature sensor has stopped working correctly, causing the system to shut down for safety.

High DIY-safe £120-190

What to check first

  1. Locate the reset button on the control panel
  2. Use a small pin or paperclip to press the reset hole for a few seconds
  3. Wait for the boiler to restart; if the error returns immediately, you will need a professional

Parts commonly replaced

  • Control thermistor (NTC sensor)
  • Flow/Return sensor

Related codes

Full explanation for E1
E5

Your boiler's burner has stopped firing for safety reasons, which means you currently have no heating or hot water.

High DIY-safe £100-250

What to check first

  1. Locate the reset button on the burner motor itself (usually behind the front casing) and press it once.
  2. Press the reset button on the main digital control panel.
  3. Check that you have fuel in your oil tank and that the isolation valve is open.

Parts commonly replaced

  • Photocell
  • Oil nozzle
  • Fuel pump
  • Control box

Related codes

Full explanation for E5
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