Haier AW07LC2VHA, Technical Overview

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OPERATIONS
PAGE 20
ENGLISH
valve. The 4 way valve will direct the hot gas to the outdoor
coil. The refrigerant will condense in the outdoor coil and be
slightly subcooled. The refrigerant is now in a liquid state.
2
Temperature Sensor Toci
The temperature of the hot gas leaving the 4 way valve will be
monitored by the Toci Temperature Sensor. This temperature
should be near the temperature of the compressor discharge
gas temperature. If it is not, there is a problem with the 4 way
valve. The ECU will detect the temperature difference and gen -
erate an Error Code.
3
Temperature Sensor Tc
This sensor monitors the temperature of the outdoor coil during
condensing operation. If abnormal condensing temperature is
detected this sensor, the outdoor fan motor speed or compres-
sor frequency may be adjusted.
4
Temperature Sensor Ta
The outdoor air temperature will be monitored by the ECU. If the
outdoor air temperature rises or falls, the speed of the outdoor
fan/positions of the EEV’s may be changed.
The refrigerant liquid will exit the outdoor coil and enter a
strainer where debris is trapped. The refrigerant liquid leaves
the strainer and bypasses the outdoor coil EEV via a path
through the check valve.
The refrigerant liquid now enters a receiver where excess
refrigerant will store. The required liquid leaves the outdoor
liquid receiver and passes through the Liquid Stop Valve.
After the liquid leaves the stop valve, it will enter the restric -
tion of the CALLING INDOOR UNIT’s EEV. The EEV will drop
the pressure of the liquid to low pressure low temperature.
5
Temperature Sensor Tc2
The EEV associated Liquid Pipe Sensor will monitor the tem-
perature of the refrigerant leaving the EEV to calculate system
superheat.
The low pressure low temperature refrigerant will enter the
mixed phase liquid line and travel to the indoor unit. Heat from
the air passing across the indoor unit evaporator will flash off
the cold refrigerant into a cold vapor.
The cold vapor will travel down the vapor line and return to the
outdoor unit via a path through the Gas Stop Valve.
6
Temperature Sensor Tc1
The EEV Gas Pipe Sensor will monitor the temperature of the
suction gas to calculate the difference between Liquid Pipe
Temperature and Gas Pipe Temperature. This calculation is the
suction vapor superheat. If a change in EEV port opening size is
needed, the EEV will make a small adjustment.
The vapor refrigerant will then enter the 4 way valve and be
directed to the Compressor suction accumulator. The ac
-
cumulator will trap any liquid refrigerant that may enter the
compressor and potentially damage it.
The vapor will exit the accumulator and enter the compressor.
The refrigeration cycle will continually repeat until the de
-
mand for cooling ends.
7
Temperature Sensor Ts
The temperature of the suction gas entering the compressor
is monitored by the Suction Temperature Sensor. If abnormal
temperature either hot or cool is detected, the frequency of the
compressor may be adjusted or the system may stop operation
to protect the compressor.
During the call for cooling, the indoor air temperature will get
closer to setpoint and demand will ease. The compressor will
reduce frequency as the demand decreases. Should an addi
-
tional indoor unit call for cooling, the demand will increase and
the compressor speed will increase.
When the temperature setpoint of the indoor units is met, the
indoor units will continue to run but the outdoor unit will shut
off. This is normal operation.
OUTDOOR UNIT SEQUENCE OF OPERATION
Cooling Mode Sequence of Operation