BoilerFaultCodesBaxi H.03 .54 Fault Code
Also written as H0354 — same fault.
The Baxi H.03 .54 fault code means: your boiler has shut down because it keeps losing its flame, possibly due to a problem with the internal sensor that detects it or an unstable electricity supply.. It appears on 5 Baxi models in our database.
Technical description: Temporary flame loss Shutdown due to the power supply voltage being too low ELECTRODE PROBLEM Check the electrode electrical connections Check the condition of the electrode GAS SUPPLY Check the gas inlet pressure Check the gas valve calibration FLUE GAS EXHAUST PIPE Check the air intake and flue gas exhaust terminal Check the power supply voltage
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Baxi models that show the H.03 .54 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Baxi H.03 .54 fault code information on this page is sourced and cross-checked against the official Baxi service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026