LG Heat Pump Error Code CH27

CH27 indicates a PSC or PFC fault caused by overcurrent at the IGBT or PFC module in the inverter drive assembly. The system detected current levels beyond safe limits and shut down to protect the inverter components. The root cause can be a wiring issue, compressor fault, unstable input power, a failing DC link capacitor, or a damaged IGBT module. A technician needs to systematically test each of these areas to identify the specific failure.

No. CH27 is a protective fault that shuts the unit down to prevent damage or a potentially dangerous overcurrent condition. Attempting to force the unit to operate with this fault active risks destroying the inverter board, burning compressor windings, or creating an electrical hazard. The system should remain off until the fault is diagnosed and corrected.

Repair cost depends heavily on what component has failed. Wiring repairs and connection tightening are relatively inexpensive, typically in the range of $75 to $200 for a service call. A DC link capacitor or PFC board replacement generally runs $200 to $600 including parts and labor. An IGBT module or full inverter board replacement can range from $400 to $1,000 or more depending on the model. Compressor replacement is the most expensive outcome, often ranging from $800 to $2,000 or higher.

Some basic checks, such as inspecting wire connections and verifying that the circuit breaker is supplying the correct voltage, are within reach of a knowledgeable homeowner. However, diagnosing compressor insulation resistance, DC link capacitor condition, and IGBT module integrity requires specialized tools and working with high-voltage DC bus circuits, which can be lethal. Most of the repair work for CH27 should be performed by a qualified HVAC or refrigeration technician.

A power reset may temporarily clear the fault display, but CH27 will return if the underlying cause is not corrected. If the fault reappears quickly after a reset, the issue is active and progressive. Repeated resets without repairs can cause additional damage to the IGBT module or compressor windings and should be avoided.