Common problems guide

The most common Firebird Enviro System problems

The faults most likely to send a Firebird Enviro System into lockout — with plain-English causes, what to check first, estimated repair costs and whether you need a Gas Safe engineer.

13 documented codes
6 most common
6 DIY-safe checks
0 engineer needed

The 6 most common faults

01
E5 High DIY-safe

Your boiler's burner has stopped working for safety reasons, meaning the system cannot fire up to provide heat or hot water.

What to try first

Check that you have enough heating oil in your storage tank.Ensure the oil supply valves are fully open.Press the reset button on the burner control box once; if it fails again, do not keep resetting it and call an engineer.

Est. cost
£90-250
Parts
Photocell, Oil nozzle, Fuel pump
Full guide for E5
02
High limit High DIY-safe

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

What to try first

Check that all radiator valves are open and not turned off.Ensure there is enough water pressure in the system by checking the pressure gauge.Press the manual reset button located on the control panel or behind the front cover.

Est. cost
£120-350
Parts
Circulation pump, High limit thermostat, System filter (cleaning/replacement)
Full guide for High limit
03
Burner Lockout A High DIY-safe

Your boiler has stopped working because it cannot get enough oil to keep the flame going.

What to try first

Check the oil level in your storage tank to ensure you haven't run out.Inspect the oil supply line valve to make sure it is fully open.Press the illuminated reset button on the burner once; do not press it more than twice.

Est. cost
£90-180
Parts
Oil filter, Photocell, Oil pump
Full guide for Burner Lockout A
04
Burner Lockout B High DIY-safe

Your boiler has stopped working because it has detected an issue with its electricity supply or internal wiring.

What to try first

Check if other electrical appliances in your home are working to rule out a power cut.Ensure your boiler's power switch or fused spur is turned on.Press the manual reset button on the burner control box once to see if the system restarts.

Est. cost
£90-250
Parts
Burner Control Box, Internal Wiring Harness, Capacitor
Full guide for Burner Lockout B
05
Burner Lockout C High DIY-safe

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

What to try first

Check that you have enough oil in your storage tank.Ensure the oil supply valves are fully open.Press the illuminated manual reset button on the burner once only.

Est. cost
£120-350
Parts
Photocell, Oil nozzle, Ignition transformer
Full guide for Burner Lockout C
06
Burner Lockout D High DIY-safe

Your boiler's burner has stopped working for safety reasons, meaning the system cannot fire up to provide heating or hot water.

What to try first

Check that you have enough heating oil in your storage tank.Ensure the oil supply valves are fully open.Press the illuminated reset button on the burner once; if it fails to restart or locks out again immediately, do not keep pressing it.

Est. cost
£120-350
Parts
Oil nozzle, Photocell, Control box
Full guide for Burner Lockout D

on the Firebird Enviro System

PhotocellOil nozzleFuel pumpControl boxCirculation pumpHigh limit thermostat

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
See the full 13-code list for the Firebird Enviro System