BoilerFaultCodesIdeal L5E Fault Code
The Ideal L5E fault code means: your heat pump’s main engine is struggling to pull enough power to start up correctly.. It appears on 1 Ideal model in our database.
Technical description: Compressor Start Error
What causes the Ideal L5E fault?
This fault occurs when the heat pump's compressor tries to turn on but cannot reach its required operating speed. It is usually caused by an electrical component failing to provide the initial 'push' needed to start the motor, or a blockage preventing the internal parts from moving freely.
This issue is more frequent during the first cold snap of autumn, as components that have sat idle during the summer may struggle to restart under increased demand.
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 L5E fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal L5E 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