BoilerFaultCodesThe 6 most common faults
01
2 High Engineer
Your heating system has detected an internal wiring or connection fault, which stops it from working properly to keep you safe.
Full guide for 202
4 High Engineer
Your boiler is trying to start up, but it cannot detect a flame because gas is not getting through properly or the ignition isn't sparking.
Full guide for 403
5 High Engineer
Your boiler is having trouble lighting or staying lit because it cannot detect a steady flame, which is likely due to a blocked drainpipe, low gas supply, or an ignition issue.
Full guide for 504
6 High Engineer
Your boiler is failing to detect a proper flame, so it has safely shut itself down to prevent any gas from building up.
Full guide for 605
8 High Engineer
Your boiler has detected an issue with the internal fan that blows exhaust gases safely outside, causing it to stop working so the heating and hot water have turned off for safety.
Full guide for 806
27 Low Engineer
Your boiler has lost its connection to the weather sensor outside, but your heating and hot water should still continue to work normally using default settings.
Full guide for 27on the Daikin EKOMB 22 Combi
Cable harnessSwitch S1Switch S2Ignition electrodeGas valveIgnition lead
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 Daikin 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
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