Samsung Air Conditioner Error Code E320

The E320 error code on a Samsung air conditioner indicates a main cooling solenoid valve open circuit fault. The solenoid valve is an electrically controlled valve within the refrigerant circuit that regulates the flow of refrigerant to the indoor unit or between stages in a multi-zone or heat pump system. An "open error" specifically means the control board has detected an open circuit condition in the solenoid valve coil, meaning electrical continuity through the coil has been lost entirely.

This type of fault typically originates in one of three areas: the solenoid valve coil itself, the wiring harness connecting the coil to the main control board, or the control board output circuit that drives the valve. A burned or broken coil will present infinite resistance when measured with a multimeter across its terminals, compared to the expected low resistance reading of a functioning coil. Damaged wiring, corroded connectors, or a broken pin in the harness can produce the same open circuit reading even when the coil itself is intact.

When this fault is active, the system cannot properly control refrigerant flow through the main cooling circuit, which will prevent normal cooling operation or cause the unit to shut down on a protective fault. The error will typically persist until the root cause is corrected and the fault is cleared from the control board. Technicians should inspect the solenoid valve coil resistance, check all wiring and connectors between the valve and the board, and verify the board output voltage during a commanded valve activation cycle.