BoilerFaultCodesThe 6 most common faults
01
Activate BCC High DIY-safe
Your boiler has recently had its main computer chip replaced and is waiting for you to restart it to complete the final setup.
What to try first
Locate the Reset button on the front control panel.Press and hold the Reset button for several seconds.Wait for the boiler to cycle through its startup sequence and check if the error clears.
02
Red LED flashing High Engineer
Your boiler has stopped working because it failed to ignite, which means it is currently unable to provide heating or hot water for safety reasons.
Full guide for Red LED flashing03
Red LED illuminated High Engineer
Your boiler has detected a safety fault and has locked itself to prevent operation, meaning you currently have no heating or hot water.
Full guide for Red LED illuminated04
0011 High Engineer
Your boiler has failed to light the flame after several attempts and has switched itself off for safety reasons.
Full guide for 001105
0001 High Engineer
Your boiler has switched itself off because it has become dangerously hot, likely due to a circulation blockage or a faulty sensor.
Full guide for 000106
Lockout flame signal High Engineer
Your boiler has stopped working because it cannot detect a flame, meaning it is currently unable to safely heat your home or water.
Full guide for Lockout flame signalon the Halstead Finest Gold
Burner Control Card (BCC)Ignition electrodeGas valvePCBAir pressure switchOverheat 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 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