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SiUS28-902_B
Outline of Control (Indoor Unit)
Function
41
6.9.2 Economizer
When indoor and outdoor temperatures are reversed, the compressor is stopped to let in the
outdoor air to save energy.
This operation is called economizer operation, and the equipment to detect indoor and outdoor
temperatures and open and close the damper to perform this operation is called an economizer.
The economizer detects indoor and outdoor temperatures, informs the air conditioner that the
economizer operation is ready, and opens and closes the damper.
The indoor unit stops the outdoor unit when it receives a signal from the economizer and
performs air supply operation.
When the indoor temperature is cooled down sufficiently by the economizer operation, and it is
no longer necessary (thermostat OFF), the indoor unit outputs a signal to the economizer to
close the damper.
Note:
1 Thermostat ON signal: A signal to turn ON the indoor unit thermostat and allow the
economizer to open the damper.
It turns ON the relay on the “X8A side of X23A” on the PCB for additional I/O.
2 External input ON is an input signal to the “X11A” terminal on the PCB for additional I/O.
3 To stop the compressor while the economizer is in operation to save energy.
4 Remote control ON signal: Contact output which shows the operating status of the indoor
unit. This signal turns on the relay “on the opposite side of X8A of X23A” on the PCB for
additional I/O.
6.9.3 Air Purifier
When an air purifier is connected onsite, the fan is operated with the airflow rate set of the
remote controller or with the H tap.
Note:
1 External input ON is an input signal to the “X25A” terminal on the PCB for additional I/O.
&
Elimination of others
Remote control ON
Remote control OFF
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Elimination of others
Normal operation
•
Transfer the thermostat OFF state to the
outdoor unit.
∗
3
•
EV = 0 pls
•
The remote controller indicates cooling
operation.
•
The fan tap follows the remote controller.
Transfer indoor unit ON signal
∗
4 to the
economizer.
Stop indoor unit ON
signal
∗
4 to the economizer.
•
Cooling mode
•
When the thermostat is ON
•
External input = ON
∗
2
Transfer Thermostat ON signal
∗
1 to the
economizer.
•
Cooling mode
•
When the thermostat is ON
Stop Thermostat ON
signal
∗
1 to the economizer.
•
Remote control operation
(including thermostat OFF)
•
External input = ON
∗
1
Fan x tap operation
(Same operation as with the airflow rate selected
with the remote controller)
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