Haier AW09EH2VHD Service Manual page 16

Terminal
The unit terminal block receives electrical power from the
outdoor unit. There are 4 connections for electrical wires.
Terminals 1 and 2 are connected to terminals 1 and 2 of the
outdoor unit. This wiring supplies power to the indoor unit.
Terminal 3 is a communication wire. The indoor unit sends
indoor air temperature, coil temperature and temperature
setpoint information to the outdoor unit on this wire. If a
splice or break in this wire is present, the indoor unit will not
be able to communicate with the outdoor unit. The ERROR
CODE will be an E7.
Displ
The indoor display has an infrared communication circuit that
receives operating commands from the remote control. This
display will indicate operating modes, error codes, indoor air
temperature, timer status, and
PAGE 16
Block
ay
●
power status.
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INDOOR UNIT CONTROLS and COMPONENTS
Ambient Temperature Sensor
The Ambient (room) Temperature Sensor is a negative
c thermistor that will decrease in resistance with
increases in room air temperature. The sensor is located on a
clip mounted in the return air stream.
The sensor connects to the control board at Plug CN-6.
Piping Temperature Sensor
The Piping Temperature Sensor is a negative
thermistor that will decrease in resistance with increases in
coil temperature. The sensor is located in a socket soldered
to the surface of the indoor coil.
This sensor will monitor the temperature of the indoor coil
in both cooling and heating modes of operation. Should
abnormally cold or hot coil temperature be detected by this
sensor the system will take steps to correct the condition sensor sensor,
or report an ERROR CODE.
The sensor connects to the control board at Plug CN-6.