Panasonic U-4LE1E5, Service Manual, Page: 13 / 133

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Mini VRF SYSTEM
Control Functions
3. Special Controls
•
In addition to ordinary heating and cooling operation, this system also includes the following 4 types of special
controls for control of the system as a whole:
3-1. Oil discharge prevention device control
3-1. Oil discharge prevention device control
3-2. Reverse cycle start control
3-3. Inter systems refrigerant oil recovery control
3-4. Reverse cycle defrost control
Perform an oil discharge prevention control when starting from the stop mode.
When starting the operation after a long hour-stop mode under a low outdoor air temperature,
control the oil discharge prevention without rapidly increasing the compressor's frequency to avoid draining
the condensed refrigerant together with oil until the overheating inside the compressor is decreased.
• In order to judge as to whether the compressor is to be started when in a high temperature state,
a starting pattern will be changed according to the discharge temperature.
(1)
(1-1) Discharge temperature: less than 30°C
(1-2) Discharge temperature: over 30°C
*1
*2
*3
*4
Td: Discharge temperature
HPT: High pressure saturated temperature
K: Difference in temperature (1K=1°C)
Elec. cont. valve: Electronic control valve
Control in the Cooling Mode
Control hour
Outdoor unit
Indoor unit
Compressor
Fan
Elec. cont. valve*4
Frequency 44Hz (Max. 3 minutes) 54Hz
Preset wind speed or fixture setting to "Lo" by indoor unit control system
All indoor units' elec. cont. valve are fixed to a certain pulse according to the capacity.
Min. 1 minute 30 seconds to Max. 12 minutes.
(Discharge degree-of-overheating: Td*1 - HPT*2>10K*3)
Control hour
Outdoor unit
Indoor unit
Compressor
Fan
Elec. cont. valve*4
Frequency 22Hz
Preset wind speed or fixture setting to "Lo" by indoor unit control system
All indoor units' elec. cont. valve are fixed to a certain pulse according to the capacity.
Min. 1 minute to Max. 5 minutes (Discharge degree-of-overheating: Td-HPT>10K)
NOTE
SM830195-01̲Mini VRF SYS.indb 7 SM830195-01̲Mini VRF SYS.indb 7 2011/12/20 16:31:03 2011/12/20 16:31:03