Specialcontrols; Special Controls - Panasonic U-4LE1E5 Service Manual

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
3-2. Reverse cycle start control
3-3. Inter systems refrigerant oil recovery control
3-4. Reverse cycle defrost control
3-1. Oil discharge prevention device 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) Control in the Cooling Mode
(1-1) Discharge temperature: less than 30°C
Control hour
Outdoor unit Compressor
Fan
Indoor unit
Elec. cont. valve* 4
(1-2) Discharge temperature: over 30°C
Control hour
Outdoor unit Compressor
Fan
Indoor unit
Elec. cont. valve* 4
NOTE
*1 Td: Discharge temperature
*2 HPT: High pressure saturated temperature
*3
K: Difference in temperature (1K=1°C)
*4 Elec. cont. valve: Electronic control valve
Min. 1 minute 30 seconds to Max. 12 minutes.
(Discharge degree-of-overheating: Td* 1 - HPT* 2 > 10K* 3 )
Frequency 44Hz (Max. 3 minutes)
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)
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.
1 - 7
Mini VRF SYSTEM
54Hz
Control Functions
1