Service and Parts Manual (2019, 2020, 2021, 2022)

21 PB
OPERATION
Air ow direction (Louvers) control
The louver is operated by a stepper motor and operates the horizontal swing of the louver automatically. Press the SWING
button to start or stop the louver swing.
During the louver swing in normal operation, the current position will be stored. When the appliance turns off and the louvers
swing automatically to the default position, it will position at the close position plus 5º.
4-way valve
State: It is interrupted in cooling.
Switchover: When initially powered on for cooling, the 4-way valve is interrupted immediately.
When the heating is changed to the cooling, it needs an interval of 50 seconds for the 4-way valve to change over from being
activated to being interrupted.
Heating-run mode
Temperature compensation
The temperature compensation is 5º in heating mode. For example, if the set temperature is 77ºF(25°C) by the remote
control, when the room temperature is detected with 88ºF(31°C), the compressor will turn off. The main reason is that the hot
air is condensed at the top of the house.
Note: The compensation is available only if the room temperature sensor of indoor unit is used and it is not available when it
is subject to the sensor on the remote control.
Indoor fan motor operation
Anti-cold air system:
When the appliance run in Heat mode condition, the indoor fan motor operation is shown in Figure 303 to prevent the cooling
air come out during the appliance operation.
95ºF
86°F
77°F
When the difference between the setting temperature and the room temperature equal to 2º or 4º, the indoor fan speed will
keep in current speed.
Air ow direction control
The horizontal louver is controlled by a step motor, press the SWING button to swing or stop the louver.
During the louver run in normal operation, the current position will be stored. When the appliance turn off and louver swing
automatically to the default position, it will position at the default position plus 5º.
Outdoor fan
The outdoor fan speeds except single speed motor can be changed according to outdoor ambient temperatures.
4-way valve
State: It is electried in heating.
Switchover: When initially powered on for heating, the 4-way valve is activated immediately.
In the change from cooling to heating, it needs an interval of 50 seconds for the 4-way valve to change over from being
interrupted to being activated.
The super function (option)
In cooling mode, when you press the SUPER button by remote control, the unit will operate for 15 minutes with the following
setting:
a. The set temperature is 16º(61°F);
b. The fan speed with highest speed;
c. The compressor runs with high frequency.
Figure 303