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3. Compressor Control
3. Compressor Control
6-1. Evaporation temperature (= Te) control
The cooling capacity is adjusted with this control. It prevents freezing of the indoor unit heat
exchanger and the dew to the outside panel of the indoor unit. The capacity is adjusted according
to the following figure.
Evaporation temperature area
1
Te_tgt_max.
Te_tgt_min.
The evaporation temperature area changes depending on the maximum load level in each indoor
unit as shown on previous page.
The Area C is regarded as Area B for 6 minutes after compressor starts.
When the system operates in a minimum capacity, the system will continue operating for at least
6 minutes if the evaporation temperature area is Area C.
During special controls such as defrosting or oil recovering between the systems, the compressor
capacity will not be controlled by the evaporation temperature control area.
If the outdoor unit is stopped while the evaporation temperature is in Area C, the system may
operate from the lower compressor capacity when starting next time.
Test run mode
Test run mode in cooling operation is used when the room temperature is low and the indoor unit
thermostat is not turn ON. This mode is used for operation check when the outdoor unit is fully
operated or additional refrigerant charge without stopping the system.
*
If the test run is continued for a long time, the mist may occur but it is not abnormal.
If more than 1 indoor unit is in test run mode, the evaporation temperature control is not applicable.
Once the indoor unit is selected for the test run, the thermostat will not be turned OFF.
After the last indoor unit is operated in the test run mode, the test run is automatically cancelled
after 1 hour.
6-2. Condensation Temperature Control
Target temperature of the Area B is different between cooling and heating operation.
1
In Cooling Mode
The purpose of this control at cooling
is to prevent abnormal high-pressure.
deg
Compressor capacity can increase
6.5
6.0
Compressor capacity
cannot increase
3.0
2.5
Compressor capacity decreases
2
In Heating Mode
Heating capacity is adjusted with this control.
It also prevents abnormal high-pressure simultaneously.
The capacity is controlled in the following diagram.
Control Functions - Outdoor unit
16.0
13.0
8.0
Area A
Area B
Area C
0
Max. required level
1 - 8
2WAY VRF SYSTEM
2WAY SYSTEM
Control Functions
unit: °C
11.0
6.0
3.0
15
30
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