BoilerFaultCodesIdeal J65 Fault Code
The Ideal J65 fault code means: your heat pump has stopped working because the internal computer that controls the motor has detected an electrical problem.. It appears on 1 Ideal model in our database.
Technical description: Inverter Error
What causes the Ideal J65 fault?
This fault occurs when the heat pump's control board detects an electrical irregularity or a communication failure with the motor that drives the heating process. It is typically caused by a component failure within the electronics or a physical fault in the compressor itself that prevents it from starting safely. In some cases, a loose connection or a sudden power surge can trigger this safety shutdown.
This fault can sometimes appear during summer or winter extremes when the compressor is required to work harder to maintain high temperature demands.
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 J65 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal J65 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