BoilerFaultCodesIdeal LC3 Fault Code
The Ideal LC3 fault code means: your heat pump has stopped working because of an internal electrical communication issue within its power control system.. It appears on 1 Ideal model in our database.
Technical description: Inverter Error
What causes the Ideal LC3 fault?
This fault occurs when the heat pump's internal computer loses the ability to communicate with the system that manages the power sent to the compressor. The most common reason is a failure of the inverter circuit board or a loose connection in the internal wiring, which prevents the unit from regulating its energy output.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Ideal models that show the LC3 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ideal LC3 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