Haier AW07LC2VHA Technical Overview page 21

4-way valve coil:
Refrigerant flow in cooling
OFF
ON
Refrigerant flow in heating
3
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 heating, the indoor unit will send the room
temperature 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 the indoor fan will remain
off.
EEV valves serving indoor circuits will step to a FULL OPEN
BYPASS position. Outdoor EEV valve serving outdoor coil
will step open to a pre-set metering position based upon the
temperature of the outdoor air.
The outdoor unit 4 way valve will be energized. Equalization
noise will be heard.
The outdoor fan motor will start.
The compressor will start in low RPS speed and gradually
speed up.
Indoor fan will begin to operate at slow speed and gradually
increase speed.
With the compressor operating, refrigerant will begin to flow
throughout the refrigeration circuit.
The operating frequency of the compressor will be displayed
on the Service Monitor Board Display.
OUTDOOR UNIT SEQUENCE OF OPERATION
Heating Mode Sequence of Operation
2
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
4
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
When the compressor starts, the compressor 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
valve. The 4 way valve will direct the hot gas to ALL of the
indoor coils.
Note: Any indoor unit that is in heating mode will have it's louver
open and indoor fan running. Non-calling indoor units will receive hot
gas but their fans will remain on very low speed with the louver open.
When demand for heat increases, the indoor fan will speed up to
meet the increased demand.
2
Temperature Sensor Tc1 and
Temperature Sensor
The temperature of Tc1 should now be hot. This will indicate
the 4 way valve is directing hot gas to the indoor coils. If it is not,
there is a problem with the 4 way valve. The ECU will detect the
temperature difference and generate an Error Code.
OPERATIONS
7
Low pressure
Suction temp.
switch
sensor
Comp-
ressor
Discharge temp.
sensor 1
Accumulator
Capillary tube
Pipe sensor
4-way valve
Toci
Outdoor
heat
exchanger
temp.
sensor
EEV O
Strainer
Receiver
Check valve
3
Indoor Heat Exchanger
6
FAN-OUT
Outdoor
ambient
temp.
sensor
Defrost
sensor
5
Distributor
PAGE 21