LG Heat Pump Error Code CH28

CH28 means the DC link voltage inside the inverter circuit has been detected as too high. The DC link is the internal high-voltage DC bus that powers the variable-speed compressor drive. LG's control system triggers this fault to protect the inverter components from overvoltage damage. The unit will not operate until the condition is corrected.

No. The unit is designed to shut down when CH28 is triggered specifically to prevent damage to the inverter board, power transistors, and capacitors. Attempting to override or ignore this fault and continue operating the system risks permanent damage to expensive internal components and could create a safety hazard.

Repair costs vary widely depending on the root cause. If the issue is simply an unstable power supply or loose wiring, a service call and minor correction may cost between $100 and $300. If the inverter board or capacitor bank needs replacement, parts and labor costs can range from $400 to over $1,000 depending on the model and component availability.

Some basic checks, like inspecting visible wiring connections and verifying the supply voltage at the disconnect, can be done by a knowledgeable homeowner. However, measuring the DC link voltage directly requires working near high-voltage inverter components, which is dangerous without proper training and equipment. If the issue involves the inverter board or capacitors, a licensed HVAC technician should handle the repair.

A power reset may temporarily clear the fault display if the overvoltage condition was caused by a brief voltage spike or transient. However, if the underlying cause, such as high supply voltage, a loose connection, or a failing inverter component, is not corrected, the CH28 code will return. Resetting without diagnosing the root cause is not a permanent fix.