Haier AU55NFIAIA Service Manual page 73

Below we will comment for the functions of some ports and some changes of PCB
0010451971 and 0010451531:
1. Control Board 0010451971
Herein, the control board we are concerned is the board without CPU. Functions for every port are as
follows:
CN301: port for power supply, connected with CN202 of the power board.
CN302: connected to testing board.
CN303: connected to the computer serial port through the testing device.
CN304: HBUS communication port.
CN305: the driving port for relay, connected to CN203 of the power board.
CN306: the driving port for IPM, connected to CN105 of the power board.
CN307, CN308: port for the heat-emitting fan. No used at present.
CN309: port for the main relay and for testing current, connected to CN104 of the power board.
CN310: the driving port for electronic expansion valve.
CN311: testing port for the radiator temperature. No used at present.
CN312: testing port for the coil temperature Tt.
CN313: testing port for the defrosting temperature Te.
CN314: testing port for the outdoor ambient temperature Ta.
CN315: testing port for the suction temperature Ts.
CN316: testing port for the discharging temperature Td.
CN317: port for low pressure switch.
CN318: port for high pressure switch.
Control board 1
Totally there are 3 types of control board, because they have different appearance, you will distinguish them
much easier.
Control board 1
is the earliest edition, because this board is rather big and it will cover the fixing screw
which supports the electric control box, also taken into consideration the convenient installation and service,
we modified and designed the Control board 2.
Control board 2
is the second edition, because there are electric parts on both sides of this board, and
Commercial Air Conditioner
Control board 2
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Model: AU55NFIAIA
Control board 3