Panasonic U-8MF2E8 Service Manual page 25

4. Output of PCB
4-8-3. Expansion Valve for Heat Exchanger Control
The configuration of the heat exchangers is different depending on the capacity of the outdoor unit.
Operation of electronic control valves during normal unit operation
Normal
All
Low ambient
cooling
temperature
mode
All
heating
System stopped
mode
Other outdoor
units operating
Heat exchanger
[condenser] of
outdoor unit
Mixed
cooling/
heating Heat exchanger
[evaporator] of
operation
outdoor unit
When operating in all cooling or all heating mode, the heat exchangers of which the compressors are driving in the
outdoor units are used.
However, when operating in cooling mode with low ambient temperature, the number of pieces for using the heat
exchanger is changed according to the operating condition of indoor units and the status of outdoor units.
When operating in mixed cooling/heating mode, the condition and the number of pieces for using the heat exchanger
are changed according to the operating condition of indoor units and the status of outdoor units.
The heat exchanger is selected in turn from the outdoor unit heat exchanger 1 as the shortest operating time of the
inverter compressor.
SH control is controlled so that the difference of temperature between the liquid tube temperature and gas tube
temperature should be set within the range as shown below.
Mixed cooling/heating operation (Heat exchanger [evaporator] of outdoor unit)
Status of
heat exchanger
Condenser
Condenser
Stop
Evaporator
Stop
Stop
Condenser
Stop
Evaporator
Stop
Outdoor unit Capacity
All heating mode
1 - 17
MOV1 MOV2
Maximum flow control
480 480
120∼480 105∼480
Heat exchanger capacity control
0 0
Refrigerant shut-off
20∼480 20∼480
SH control
0 0
Refrigerant shut-off
0 0
Refrigerant shut-off
65∼480 50∼480
Heat exchanger capacity control
0 0
Refrigerant shut-off
20∼480 20∼480
SH control
0 0
Refrigerant shut-off
3WAY SYSTEM
Control Functions
Remarks
Target value of SH control
-1 ~ 5°C
2 ~ 5°C
1