Control Specification SiUS12-81456 Function and Control3.15 Wiring-Error CheckOutline The convenient Wiring Error Check function is designed for the microcomputer to automaticallycorrect wiring errors.If local wiring cannot be determined due to buried piping just press the wiring-error check switchthat is behind the right-hand panel of the outdoor unit. Even if the connections for Room A andRoom B are confused, the system may run. Note that this check function does not work in thefollowing cases: For about 1 minute after the power is turned on (during initial setup). For 3-minute standby period after the compressor has stopped. When the outdoor air temperature is below 41°F. If the indoor unit is malfunctioning (also in case of all-room transmission failure).When the piping and wiring are perfect, there is no need to use this function.Operation 1. Remove the 5 screws from the service panel (right side panel) and detach the panel.2. Press the wiring error check switch on the service monitor PCB, and the wiring error checkfunction is activated.3. In about 10-15 minutes, the checking will end automatically.4. When the checking is over, the service monitor LED indicators start flashing.Self-correction complete…The LED indicators 1 ~ 2 (18 class), or 1 ~ 4 (32 class) flash one afteranother.Self-correction impossible…The LED indicators flash all at the same time. Transmission failure occurs at any of the indoor units. The indoor unit heat exchanger thermistor is disconnected. An indoor unit is in trouble (if a trouble occurs during the wiring error checking).Emergency stop…Any of the LED indicators 1 ~ 4 stays on.Note: 1. It takes about 10-20 minutes (after pressing the wiring error check switch) to complete thechecking. (Wrong wiring between the upper and lower units cannot be self-corrected.)2. Wrongly connected liquid and gas pipes cannot be self-corrected either. Be sure to make theliquid pipe and the gas pipe in pairs.3. To force-terminate the wiring error check procedure while in progress, press the wiring errorcheck switch again.In this case, the microcomputer's memory gets back to its initial status (Room A wiring → Port Apiping, Room B wiring → Port B piping).4. In replacing the outdoor unit PCB, be sure to use this function.5. Make the power side setting after doing the wiring error checking. Otherwise, if the wiring isreversed, the air-conditioners being connected are set up in the reverse way.Basic Knowledge This function works in this way: Refrigerant flows from Port A and on. The temperatures of theindoor unit heat exchanger thermistors are detected one by one to check the matching betweenthe pipes and wiring. With this function on, a freezing (crackling) noise may be heard from the indoor unit. This is nota problem and is happening because the heat exchange temperature is made to drop below32°F in order to increase the detection accuracy. The indoor fan is prompted to turn on and off at the same time.LED 1 2 3 4 JudgmentStatus All flashing at once Self-correction impossibleFlashing one after another Self-correction complete