Auto Mode; Dry Mode; Overview; Indoor Unit - Haier AW09ES2VHB Service Manual

Auto Mode

With the system turned on, press the AUTO button on the
remote control. The system will change to the auto mode of
operation.
As the room is cooled or heated, the system will automati-
cally switch between cool mode, fan mode, and heat mode.
There is a minimum 15 minute operating time between mode
changes.

Dry Mode

Overview

The temperature control range in Dry mode is 60°F - 86°F.
This mode is used for the purpose of dehumidification.
(Tr = room temperature Ts = set temperature)
When Tr > Ts + 4°F, the compressor will turn on and the indoor
fan will operate at the set speed.
When Ts ≤ Tr ≤ Ts + 4°F, the compressor will operate at the
high dry frequency for 10 minutes, then at the low dry mode
for 6 minutes. The indoor fan will operate at low speed.
When Tr < Ts, the outdoor unit will stop, and the indoor fan will
stop for 3 minutes, then operate at the low speed option.
Automatic fan speed:
When Tr >= Ts + 9°F, High speed
When Ts + 5.4°F ≤ Tr < Ts + 9°F, Medium speed
When Ts + 3.6°F ≤ Tr < Ts + 5.4°F, Low speed
When Tr < Ts + 3.6°F, Light speed
Note: TURBO and QUIET mode must be set using the remote
controller.
If the outdoor fan is stopped, the indoor fan will pause for 3
minutes.
If the outdoor fan is stopped for more than 3 minutes, and the
compressor is still operating, the system will change to light
speed mode.

Indoor unit

To enter the dry mode, point the infrared remote control at
the indoor unit and press the power button, then press the
DRY mode button if not already set to dry mode.
The signals received by the infrared receiver are relayed to
the main board of the indoor unit to turn the system on and
set it to dry mode.
The indoor unit main board will activate the display of the
indoor unit, illuminating the display, indicating the room tem-
perature and current status of the unit.
The indoor unit main board will signal the louver stepper mo-
tor to open the louver to either a stationary position, or one
of several oscillating modes.
As the louver opens, the indoor unit main board will power up
the indoor fan motor, operating the fan at the speed last set.
The indoor fan motor has a feedback circuit which provides
the indoor unit main board with information for controlling
the speed of the fan motor. (See overview section for more
information.)

Temperature Sensors

The indoor unit has two sensors that provide temperature
information to the indoor unit main board. An indoor ambient
temperature sensor, and coil temperature sensor are used for
controlling the system during dry mode. The resistance val-
ues of the sensors will vary with temperature. The resistance
to temperature values can be found using a temperature /
resistance chart specific to the sensor being checked.

Communication

The indoor and outdoor unit main boards communicate via
a digital signal on the wire connected to terminal 3C of each
unit. A splice or break in this wire will cause a communication
error.
When a command is received from the remote control, the
indoor unit main board communicates with the outdoor unit
main board via the terminal 3C wire to perform the requested
function.

Outdoor Unit

Upon a request for dry mode, the outdoor unit main board
applies power to the outdoor fan motor and compressor.
Depending on system cycling, there may be up to a 3 minute
wait period before the compressor and outdoor fan start.)
WARNING: Do not measure compressor voltages, damage to
the volt meter may result.
The outdoor unit main board also controls the position of
the EEV (Electronic Expansion Valve) to regulate the flow of
refrigerant to the indoor unit evaporator coil.
Temperature Sensors
Four temperature sensors located in the outdoor unit provide
temperature information to the outdoor unit main board for
control of the system during dry mode.
The outdoor ambient temperature sensor provides the tem-
perature of the air drawn into the outdoor coil of the outdoor
unit.
The defrost temperature sensor provides the temperature
sensed at the output of the outdoor coil.
SEQUENCE OF OPERATION PAGE 25