LG Heat Pump Error Code 23

Error code 23 on an LG heat pump means the DC link circuit did not charge to at least 320VDC within 45 seconds after the starting relay turned on. This is a protection fault that prevents the inverter drive and compressor from operating on an improperly charged electrical bus. The most common causes are a failed starting relay or a problem with one or more of the three-phase input power connections.

No. Error code 23 is a protective shutdown and the unit will not allow the compressor to run while this fault is active. Attempting to force the system to operate with an undercharged DC link could damage the inverter drive, compressor, or both. Leave the system off and have the fault diagnosed before attempting to restart.

Repair costs depend on which component has failed. A starting relay replacement is typically the least expensive repair, often in the range of $100 to $300 including labor. Replacing DC link capacitors or a rectifier bridge may run $200 to $600 or more. An inverter or main control board replacement is the most expensive scenario, potentially ranging from $500 to well over $1,000 depending on the unit model and labor rates in your area.

Some basic checks are within reach of a knowledgeable DIYer, such as inspecting the R, S, and T input power connections for loose wiring or a tripped breaker. However, diagnosing and replacing the starting relay, DC link capacitors, or rectifier bridge involves high-voltage DC circuits that are dangerous without proper training and equipment. Component-level inverter repairs are best left to a qualified HVAC technician.

A power cycle may temporarily clear the fault display, but if the underlying problem with the starting relay, input power, or internal components is still present, the error will return at the next startup attempt within the 45-second charging window. A reset alone does not fix the root cause and repeated fault cycles can stress the drive components further.