BoilerFaultCodesIdeal HF Fault Code
The Ideal HF fault code means: your boiler has detected a signal for a flame when there shouldn't be one, or there is an electrical fault within the ignition system preventing it from starting safely.. It appears on 5 Ideal models in our database.
Technical description: FLAME DETECTION - SHORT CIRCUIT
What causes the Ideal HF fault?
This fault occurs when the boiler's control system detects an electrical signal suggesting a flame is present before the ignition process has even started. The most common cause is a surge or short circuit in the internal wiring, or moisture buildup on the sensing probe that tricks the system into seeing a 'ghost' flame. Because the boiler cannot verify that it is safe to light, it shuts down as a critical safety precaution.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Gas Safe Register →Ideal models that show the HF fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal HF fault code information on this page is sourced and cross-checked against the official Ideal service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026