LG Air Conditioner Error Code 207

Error code 207 on an LG air conditioner indicates a communication error between the Master Main PCB and the Slave Main PCB inside an HR (Heat Recovery) unit. These two boards must exchange data continuously for the system to operate correctly. When that communication is interrupted or was never established, the system logs code 207 and stops normal operation. A common cause is an incorrect dip switch setting on the Slave Main PCB.

Error code 207 is not a safety emergency in the way that a refrigerant leak or electrical short would be. However, the system will not operate normally while this communication fault is active, which means the unit cannot properly control refrigerant distribution or zone operation. You should avoid repeatedly powering the system on and off and have a technician diagnose the fault promptly.

If the fix is simply adjusting the dip switch setting on the Slave Main PCB, the cost would typically cover only a service call fee, generally in the range of $75 to $150 depending on your area. If wiring repairs are needed, costs can increase to the $150 to $350 range. Replacing a Main PCB is the most expensive scenario, with parts and labor potentially ranging from $400 to $900 or more depending on the specific unit model.

Start by checking Dip switch No. 5 of the SW02E bank on the Slave Main PCB and confirm it is set to the ON position. If the switch setting is correct, inspect the communication wiring harness between the Master and Slave PCBs for loose connectors, damaged insulation, or broken wires. If wiring is intact and the switch is properly set, one of the two main control boards may need to be replaced by a qualified technician.

A power reset may temporarily clear the error display, but if the underlying cause, such as an incorrect dip switch setting, faulty wiring, or a failed PCB, has not been corrected, the code will return as soon as the system attempts to re-establish communication between the two boards. A reset alone is not a fix for this error.