Panasonic U-8ME2E8 Service Manual & Test Run Service Manual page 20

3. Compressor Control
3. Compressor Control
When the temperature falls in the Area D (over PX temperature), the operation stops within 0 to
30 seconds at the interval of the roadmap control.
After Tc falls in the Area D and the thermostat is turned OFF, the system may resume operating
from the lower compressor capacity.
When the system operates in a minimum capacity, the system will continue operating for at least
6 minutes if the condensation temperature area is the Area C.
If it maintains in the Area C, the thermostat may turn OFF.
1
Test Run
Test run mode in heating operation is used when the room temperature is high and the indoor unit
thermostat is not turned ON. This mode is used for operation check when the outdoor unit is fully
operated or additional refrigerant charge without stopping the system.
Once the indoor unit is selected for the test run, the thermostat will not be turned OFF.
However, condensation temperature control is performed in order to prevent the high load
according to the figure shown on previous page.
After the last indoor unit is operated in the test run mode, the test run is automatically cancelled
after 1 hour.
6-3. Protection Control
1 Compressor discharge temperature protection
The compressor capacity is controlled according to the figure below.
* Discharge temperature that is used for this control is the highest temperature among all compressors.
2 Low pressure protection control
In order to prevent the excessive decrease of low pressure, the compressor capacity is controlled
according to the figure below.
Low pressure
MPa
°C
Compressor stops
106
105
Compressor capacity
decreases
104
103
Compressor capacity cannot increase
101
Compressor capacity can increase
No restriction
0.25
Capacity goes up slowly
0.20
Capacity cannot increase
0.17
Capacity goes down
0.06 H06 trip (Continuous for 2 minutes)
0.02 H06 trip
Control Functions - Outdoor unit
Capacity goes down 2.0HP
Capacity goes down 1.0HP
Capacity goes down 0.5HP
1 - 10
2WAY VRF SYSTEM
2WAY SYSTEM
Control Functions