Samsung Air Conditioner Error Code *1

The Samsung *1 error code indicates a room thermistor sensor fault in the indoor unit, where the asterisk represents the specific indoor unit address on a multi-unit or wired remote controller system. The room thermistor is a negative temperature coefficient (NTC) resistor that continuously monitors the return air temperature inside the conditioned space. This reading is critical to the system's ability to regulate cooling or heating output, maintain setpoint temperature, and protect the unit from operating outside safe thermal boundaries. When the indoor unit's control board detects a signal from the thermistor that falls outside the expected resistance range, it registers the *1 fault and halts normal operation.

The first diagnostic step outlined for this error is to verify that the indoor unit thermistor is physically connected at connector CN8 on the indoor unit PCB. A missing, loose, or improperly seated connector at CN8 is one of the most frequent root causes and is easily overlooked. If the thermistor is confirmed present and connected, the next focus shifts to the sensor's resistance characteristics and the condition of the wiring harness running between the thermistor and the control board.

Because the error code address prefix corresponds to the indoor unit number in a multi-split or centralized wired controller configuration, technicians should note which unit address is displayed to isolate the fault to the correct air handler. Each indoor unit operates its own thermistor circuit independently, so a fault on one unit will not directly affect others on the same system.