Samsung Air Conditioner Error Code rx

The RX error code on a Samsung air conditioner indicates a cross-installation error between the Master wired remote controller and the Slave wired remote controller on the COM1 and COM2 communication lines. In multi-unit or centrally controlled Samsung AC systems, the wired remote controllers are connected via a two-wire communication bus labeled COM1 and COM2. Each controller must be wired to the correct terminal on the indoor unit's control board. When the COM1 and COM2 terminals are swapped between the master and slave controllers, the communication protocol breaks down and the system flags this as an RX error.

The root cause is almost always a wiring error made during installation or after a service visit where communication wiring was disconnected and reconnected incorrectly. The master and slave controllers each expect to receive and transmit signals on specific polarities of the communication bus. If the polarity is reversed by swapping the COM1 and COM2 wires, the controllers cannot establish proper handshaking, and the system reports the cross-installation fault. This is a configuration and wiring issue, not a component failure in most cases.

Resolving this error requires inspecting the communication wiring between the master wired remote controller, the slave wired remote controller, and the indoor unit control board. The technician should verify that COM1 on the master controller connects to COM1 on the unit terminal, and COM2 connects to COM2 accordingly, with the same verification applied to the slave controller. Correcting the wiring and restoring power should clear the fault, assuming no underlying damage occurred from the crossed signals.