Operations - Haier AW07LC2VHA Technical Overview

The outdoor unit is capable of controlling up to 4 individual indoor units. The outdoor unit will vary compressor capacity and
outdoor fan motor speed to match the demand requirement from the indoor units. All capacity and diagnostic decisions are con-
trolled by the outdoor unit ECU. During any period where the outdoor unit is running, all indoor units must be in the same mode
of operation. If any unit is energized in a mode that opposes the first indoor unit that was turned on and set to provide cooling or
heating, the opposing unit's request will be ignored.
Throughout a call for either heating or cooling operation, the temperature sensors in the indoor and outdoor units will provide
critical temperature points to the outdoor unit ECU. If the temperatures being sensed are abnormal or trending to a level that is
potentially going to create overheating of the compressor or freezing of the indoor unit.
The frequency adjustments or system responses to temperature sensors readings are explained in the section Temperature
Sensor Responses.
4-way valve coil:
OFF Refrigerant flow in cooling
ON
Refrigerant flow in heating
Indoor
heat
exchanger
temp.
sensor
FAN-IN
Indoor
ambient
temp.
sensor
Indoor unit A
Indoor unit B
Indoor unit C
Indoor unit D
On a call for cooling, the indoor unit will send the room tem-
perature and set-point requirement to the outdoor unit ECU
via the data signal wire path. The data travels from the indoor
unit to the outdoor unit via the wire located on terminal 3.
The indoor unit's louver will open and the indoor fan motor will
start.
The outdoor unit will energize the EEV's that are controlling
refrigerant flow to the calling indoor units. The position of the
EEV valves will be set to a beginning position based upon the
outdoor air temperature.
The 4-way valve will be de-energized. After a 3 minute time
delay, the outdoor fan motor will be energized. Shortly after
the outdoor fan motor turns on, the compressor will start in
low frequency. The operating frequency of the compressor
OUTDOOR UNIT SEQUENCE OF OPERATION
Cooling Mode Sequence of Operation
6
Unit A gas pipe temp. sensor
Indoor unit A
Unit B gas pipe temp. sensor
Indoor unit B
Unit C gas pipe temp. sensor
Indoor unit C
Unit D gas pipe temp. sensor
Indoor unit D
5
Unit A liquid pipe temp. sensor
Strainer
Unit B liquid pipe temp. sensor
Strainer
Unit C liquid pipe temp. sensor
Strainer
Unit D liquid pipe temp. sensor
Strainer
Oil
separator
High pressure
switch
Gas stop valve
5/8
valve
Liquid stop vavle
EEV C
3/8
EEV D
will be displayed on the Service Monitor Board Display.
The refrigerant in the system will begin to flow. The com-
pressor will discharge hot gas into the oil separator. Oil will be
trapped in the separator and returned to the suction inlet of
the compressor via the capillary tube assembly low pressure
path.
1
Temperature Sensor Td
The temperature of the compressor discharge hot gas will be
monitored by the Discharge Temperature Sensor. If the sensor
reads too hot or cool, the frequency/status of the operation will
potentially be altered.
The hot gas will leave the oil separator and enter the 4 way

OPERATIONS

7
Low pressure
Suction temp.
switch
sensor
Comp-
ressor
Discharge temp.
sensor 1
Accumulator
Capillary tube
Pipe sensor
4-way valve
Toci
Outdoor
3
heat
exchanger
temp.
sensor
EEV O
Strainer
Receiver
Check valve
2
FAN-OUT
4
Outdoor
ambient
temp.
sensor
Defrost
sensor
Distributor
PAGE 19