LG Heat Pump Error Code E320

E320 indicates a main cooling solenoid valve open circuit error. The control board has detected that the electrical circuit for the solenoid valve, which controls refrigerant flow during cooling, is incomplete. This could be caused by a failed valve coil, broken wiring, or a faulty connector. The system shuts down to prevent operating with uncontrolled refrigerant flow.

You should not attempt to force the system to run while E320 is active. The error indicates the refrigerant flow control valve circuit is open, meaning the system cannot properly direct refrigerant during cooling operation. Running the system in this state risks compressor damage and ineffective or erratic operation. Leave the unit off until the fault is diagnosed and repaired.

A technician will start by locating the main cooling solenoid valve and disconnecting its coil connector. Resistance is then measured directly across the coil terminals using a multimeter. An open reading (infinite resistance) confirms a failed coil. If the coil reads correctly, the technician will trace the wiring harness back to the control board, checking for breaks, damaged insulation, and corroded connector pins at each junction point.

Resetting the unit by cycling power may temporarily clear the fault display, but if the underlying open circuit condition still exists the error will return immediately or as soon as the system attempts to operate the cooling solenoid valve. A reset is not a repair for E320. The wiring and valve coil must be inspected and the faulty component corrected before the system will operate reliably.

Repair costs vary depending on the root cause. If the fix is a loose or corroded connector, costs may only involve a service call fee, typically in the range of $75 to $150. Replacing a solenoid valve coil or full valve assembly generally runs $150 to $400 including parts and labor. A control board replacement is the most expensive scenario, often ranging from $300 to $700 or more depending on the model.