Specifications

Wiring Error Check Function SiUS12-928_A
219 Trial Operation and Field Settings
2. Wiring Error Check Function
Outline The convenient wiring error check function is designed for the microcomputer to correct wiring
errors itself.
If local wiring is unclear in the case of buried piping, for example, just press the wiring error check
switch that is behind the right side panel of the outdoor unit. Even if the connections for Room A
and Room B are confused, the system may run without a hassle. Note that this check function does
not work in the following 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 temperature is below 5°C (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 stop valve cover or the right side panel.
2. Press the wiring error check switch (SW3) on the service monitor PCB of the outdoor unit, and
the wiring error check function is activated.
3. In about 10 ~ 20 minutes, the check finishes automatically.
4. When the check is over, the service monitor LED indicators start blinking.
 Self-correction complete…The LED indicators 1 ~ 2 (18 class), 1 ~ 3 (24 class), or 1 ~ 4 (32
class) blink one after another.
 Self-correction impossible…The LED indicators blink 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 the
checking.
2. Wrongly connected liquid and gas pipes cannot be self-corrected. Be sure to make the liquid
pipe and the gas pipe in pairs.
3. To cancel the wiring error check procedure halfway, press the wiring error check switch again.
In this case, the memory of the microcomputer returns to its initial status (Room A wiring → Port
A piping, Room B wiring → Port B piping).
4. When replacing the outdoor unit PCB, be sure to use this function.
5. Be sure to make the power side setting after doing the wiring error check because if the wiring
is reversed, the airconditioners being connected are set up in the reverse way.
Basic Knowledge  Refrigerant flows from Port A and on. The temperatures of the indoor heat exchanger
thermistors are detected one by one to check up the matching between the piping and wiring.
 With this function on, freezing (crackling) noise may be heard from the indoor unit. This is not a
problem. This is because the heat exchanger temperature is made to drop below 0°C (32°F) in
order to increase the detection accuracy.
 The indoor fan is made to turn on and off at the same time.
LED 1 2 3 4 Judgment
Status
All blinking at once Self-correction impossible
Blinking one after another Self-correction complete