BoilerFaultCodesThe 6 most common faults
01
01 High Engineer
Your boiler has detected an electrical fault in its internal control wiring and has safely shut itself down to prevent further damage.
Full guide for 0102
02 High Engineer
Your boiler is failing to light the burner despite several attempts, meaning it cannot produce heat or hot water.
Full guide for 0203
04 High Engineer
Your boiler experienced a temporary loss of power while it was trying to shut itself down safely, which has caused it to pause operation.
Full guide for 0404
05 High Engineer
Your boiler has detected an issue caused by an external factor, such as a problem with your electrical power supply, an external sensor, or a communication fault from your heating controls.
Full guide for 0505
18 High Engineer
Your boiler has detected that the water inside the system is getting hotter than it safely should and has shut itself down to prevent damage.
Full guide for 1806
24 High Engineer
Your boiler has detected that hot water is flowing back into the system in the wrong direction or at a higher temperature than the supply water, which usually points to a sensor or circulation fault.
Full guide for 24on the Remeha Selecta
Main PCBWiring harnessControl sensorIgnition electrodeGas valveIonisation probe
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 Remeha 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