AirStage AO54FJ, Service Manual

Page: 48 / 169

04-03
4-2 COMPERESSOR OPERATION
4-2-1 Capacity control
COOLING
HEATING
The rotation speed of the compressor is decided basing on the sum of the required refrigerant amount from
the connected indoor units.
The rotation speed of the compressor is decided by detecting the indoor heat exchanger mid temperature
of the connected indoor units which is running on heating mode, so that the temperature reaches to the
target temperature.
The compressor is controlled by PI control.
The one of the largest value of the signals from the indoor units on heating operation during the heat exchanger
temperature detection is used to decide the rotation speed.
However, the rotation speed of the compressor at start-up is decided basing on the sum of the required refrigerant
amount.
4-2-2 Frequency control
On stop mode 0Hz
On operating mode 20Hz 101Hz
Minimum running frequency 20Hz
Correction
The correction of control frequency of the compressor is done by the following
conditions.
Outdoor Temperature
Pipe Length Setting
Capacity Shift Setting
Protective Operation
Note that the protective correction has the most priority when the protection function is activated.
Limit
Operation current limits as accordance with DIP-SW setting.
Rotation speed hold
When compressor starts from stop condition rotation speed keep ones holding at followings.
Hold 1 : 30sec at 30Hz
To prevent from cut down low pressure
Hold 2 : 3 min at 50Hz
To stabilized the oil level
30Hz
50Hz
30sec. 3 min
Hold 1
Hold 2