Haier AW07LC2VHA Technical Overview page 54

Indoor Unit Circuit Board
The indoor unit circuit board controls the switching functions
of the indoor unit. All control decisions are made by the
outdoor unit ECU. The indoor board has some limited
diagnostic capability which will be covered in this manual.
5
11
1 CN1 Wired Remote
L Terminal 7
2 8 DIP Switches
N Terminal
3 9
Communication Terminal CN14 Stepper Motor
4 10 CN15 Stepper Motor
5A 250V Fuse
5 11
CN13 Sensors CN6 Fan Motor
6 12
CN18 Float Switch CN9 Condensate Pump
Indoor uni t
3wire 1 4AWG
Control Wiring
Indoor uni t
3wire 1 4AWG
Control Wiring
The Indoor Unit Circuit Board communicates with the outdoor
unit ECU via a connection at Terminal Block screw 3. The
data pulse that sends the communication information can be
measured with a voltmeter placed to DCV range. From the
ground connection at the Terminal Block to the Number 3
screw connection, the voltage should pulse up and down when
data is being transmitted.
This control board has control over the fan louver movement,
manual fan blower control, indoor coil temperature and indoor
PAGE 54
SLIM DUCT TECHNICAL OVERVIEW
Slim Duct Components
6
7
8
4
1
12
2
Outdoor unit
Power
Wiring
Outdoor unit
Power
Wiring
TECHNICAL OVERVIEW
air temperature sensing functions. All operational decisions
are controlled by the OUTDOOR UNIT ECU.
The connections on the indoor board are shown here in the
schematic drawing. Line voltage to power the indoor unit
comes in on Terminal Block connections 1 and 2. Power
connects from these terminal connections to CH- 1 and
CH-2 on the circuit board. If the board does not respond to
commands and has no display, check for line voltage at these
connections. When power is present at the indoor board, the
wired controller will be energized.
The control board has a replaceable 5A 250V fuse that
protects against excessive current. If power is present at
the board but the board does not work, check for continuity
9
through the fuse. Replace if the fuse is open.
10
The indoor unit temperature sensors are connected at
Plug CN-13. When testing the calibration of these sensors,
the wires can be released from the plug by pressing on the
tension tab on the side of the plug.
There 3 motors that control the directional movement of the
accessory louver. The motor connects to the circuit board at
Plug CN-14, CN-15 and CN-16. The motors are located in the
3
louver assembly.
The blower motor is connected to the circuit board at plug
CN-6.
The Slim Duct unit has a built in condensate pump. The pump
is connected to the circuit board on Plug CN-9. The pump is
energized whenever the Float Switch indicates that water
needs to be pumped from the cassette. The float switch
connects onto the circuit board via Plug CN-18.
Built-in
Condensate
Pump and
Float Switch
The float switch and pump are located behind the removable
insulated cover next to the electrical control box. The pump
is hermetically sealed and requires no maintenance. The float
switch is a normally closed switch, that opens as water rises.
The float switch requires no maintenance.
The connection for the wired controller is made via Plug CN1