System Power; Cool Mode; Temperature Sensors; Communication - GE ASYW09CRAWA Service Manual

System Power

The 240 VAC power for the system connects to terminals
1(N), 2(L), and ground of the outdoor unit terminal block. This
terminal block also connects power to the indoor unit.
The voltage readings between terminals 1(N) and ground, and
terminals 2(L) and ground should be 120 VAC. The voltage
reading between terminals 1(N) and 2(L) should be 230 VAC.
One additional connection on the terminal block (3) is for the
communication wire between the indoor and outdoor units.
NOTE: Mis-wiring of these connections may cause improper
operation or damage to system components.

Cool Mode

Overview
The temperature control range in cooling mode is 60°F - 86°F.
The temperature set at the remote control and room ambient
temperature sensor will determine if a call for cooling is
needed.If justified, the call is communicated from the indoor
unit to the outdoor unit. The indoor unit louver will open using
a stepper motor, and the indoor fan will operate at the speed
last set. The outdoor unit will determine the position of the
EEV and speed (frequency)
of the compressor. There can be a delay of up to 3 minutes
before the outdoor unit fan and compressor start.
The speed of the indoor fan can be controlled manually by
the user or automatically by the system. The speed can be
changed between LOW, MEDIUM, and HIGH. The
predetermined conditions for automatic control are as follows:
(Tr= room temperature Ts= set temperature)
There will be a 2 second delay when manually controlling the
speed.
The outdoor unit temperature sensors; outdoor ambient,
defrost, suction line, and compressor discharge, used in
conjunction with the indoor temperature sensors (ambient
and coil), provide information to the outdoor control board
to monitor the system and regulate the frequency of the
compressor, EEV positioning, and outdoor fan speed to
achieve the desired room temperature.
When cooling has been satisfied, the compressor
will turn off, followed by the outdoor fan. The indoor unit
fan will continue to run.
If the system detects a malfunction, it may shut down, or
show an error code on the indoor unit display board and/or
outdoor PCB.
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Indoor Unit
To enter the cool mode, point the infrared remote control at
the indoor unit , press the power button, then press the COOL
button if not already set.
The indoor unit main board will activate the display The PCB
will illuminate the display, indicating the temperature and
current unit status.
The indoor unit main board will signal the louver stepper motor
to open the louver to either a stationary position, or one
of several oscillating modes.
As the louver opens, the main board will power up the fan motor,
operating the fan at the speed last set.The motor has a feedback
circuit which provides the main board with information for
controlling the speed of the fan motor.

Temperature Sensors

Ambient (room) and coil temperature sensors are used to
control the system in the cooling mode.The resistance values
of the sensors will vary with 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 3 of each unit.
A splice or break in this wire will cause a communication error.
Outdoor Unit
Upon a request for cooling, the PCB applies power to the
outdoor fan motor and compressor. Depending on system
cycling, there may be up to a 3 minute wait before the
compressor and outdoor fan start.
WARNING: Do not measure compressor voltages as damage to
the meter may result.
If the room temperature is less than the set temperature,
yet higher than 2°F below the set temperature, the
system will adjust the running frequency of the compressor
automatically.
The PCB also controls the position of the
EEV (Electronic Expansion Valve)
to regulate the flow of refrigerant to the evaporator
coil.
SEQUENCE of OPERATION