BoilerFaultCodesThe 6 most common faults
01
LED 1-2-3-4 (◯◯●◯) High Engineer
Your boiler is failing to ignite because it is not receiving enough gas to produce a flame.
Full guide for LED 1-2-3-4 (◯◯●◯)02
LED 1-2-3-4 (◯◯●●) High Engineer
Your boiler has failed to light because it cannot detect a flame, meaning you currently have no heating or hot water.
Full guide for LED 1-2-3-4 (◯◯●●)03
LED 1-2-3-4 (◯●◯●) High Engineer
Your boiler has stopped working because it is struggling to detect heat or confirm a flame is burning safely, so it has shut down to protect itself.
Full guide for LED 1-2-3-4 (◯●◯●)04
LED 1-2-3-4 (◯●●●) High Engineer
Your boiler is failing to start because it cannot detect that the internal fan is spinning correctly to vent exhaust gases safely.
Full guide for LED 1-2-3-4 (◯●●●)05
LED 1-2-3-4 (●◯◯◯) High Engineer
Your boiler's computer is experiencing a memory error and cannot detect the burner flame, meaning it has shut down for safety.
Full guide for LED 1-2-3-4 (●◯◯◯)06
LED 1-2-3-4 (●◯◯●) High Engineer
Your boiler has stopped working because it is not receiving a stable power supply or is failing to light the burner safely.
Full guide for LED 1-2-3-4 (●◯◯●)on the Halstead Wickes Combi 82/102
Gas valveIgnition electrodeGas supply regulatorIgnition leadPCBNTC Temperature Sensor
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 Halstead 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