BoilerFaultCodesThe 6 most common faults
01
Detection Fault High Engineer
Your boiler has tried to start five times but failed to ignite, so it has safely shut itself down to prevent a build-up of unburnt gas.
Full guide for Detection Fault02
lockout High Engineer
Your boiler has failed to start up after multiple attempts and has automatically turned itself off for safety.
Full guide for lockout03
C/H Sensor Fault High Engineer
Your boiler's temperature sensor is providing incorrect readings, so the heating system has stopped working to prevent potential overheating.
Full guide for C/H Sensor Fault04
Detection lockout High Engineer
Your boiler has stopped working because it cannot light the internal flame or detect that it is burning correctly.
Full guide for Detection lockout05
No flow High Engineer
Your boiler has stopped working because it cannot detect that water is moving through the system as it should.
Full guide for No flow06
Lock-out High Engineer
Your boiler has failed to start after several automated attempts and has safely shut itself down to prevent a gas build-up.
Full guide for Lock-outon the Ideal Concord Cxdi
Ignition electrodeGas valveControl board/PCBControl PCBCentral Heating NTC ThermistorWiring harness
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 Ideal 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