BoilerFaultCodesIdeal H4 Fault Code
The Ideal H4 fault code means: your heat pump is shutting down because it has detected a recurring electrical surge in its motor system, preventing it from operating safely.. It appears on 1 Ideal model in our database.
Technical description: Inverter High Current (L1E/L11/L12) 3 times within 60mins
What causes the Ideal H4 fault?
This fault occurs when the electrical component that drives the compressor detects that it is drawing too much power, forcing the system to shut down to prevent damage. The most common reasons are a malfunctioning inverter board that can no longer regulate current or an internal electrical failure within the compressor itself. In some cases, external power fluctuations or loose wiring connections can also trigger this safety response.
This fault is more common during summer months when higher outdoor temperatures can cause the compressor to work under increased pressure, leading to higher electrical demand.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Ideal models that show the H4 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal H4 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 7 July 2026