BoilerFaultCodes PH Low
Boiler Fault Code PH
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code PH appears across 1 boiler brand and 3 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler is not broken; it is simply in 'Installer Mode' which is used during setup or testing and can be exited by adjusting the control knobs. (As reported on Ideal Logic Code Combi ESP1)
Pick your boiler brand for the PH fix
Source
Information for the PH fault code is sourced from the official service / installation manual for each model that displays it. Read more about how we source fault codes →
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026