Panasonic U-120ME2U9 Service Manual page 22

4. Special Control
4. Output of PCB
(4) Refrigerant Balance Valve [RBV]
The main purpose of this valve is to adjust the flow of refrigerant (refrigerant volume) in the evaporator.
When the outdoor unit receives a sign of overcharged refrigerant, the valve opens and refrigerant is recovered at the
receiver tank.
This valve also turns ON in order to recover refrigerant at the outdoor unit after heating operation is stopped.
* It is possible to set the RBV to valid or invalid by the outdoor unit EEPROM settings.
Initial setting is invalid.
* This valve is never turned ON with the RCV at the same time.
This valve turns ON for 20 seconds after heating operation is stopped, and then turns OFF.
This valve turns OFF when an abnormal drop in compressor discharge gas temperature is detected.
This valve turns OFF when an abnormal drop in compressor suction gas temperature is detected.
1
After the valve turns from ON to OFF, it will not turn ON again for 15 minutes.
This valve turns ON when low pressure sensor decreases 24.7psi (0.17MPa) at stopped system.
This valve turns OFF when low pressure sensor increases 29psi (0.20MPa).
2
RCV
HP
RBV
LP
3
Receiver tank holds a low refrigerant volume.
4
RCV
HP
RBV
LP
5
Refrigerant gas in the top of receiver tank is absorbed into low pressure side.
6
7
8
9
ON
Condenser
Liquid flow
Two-phase flow
Over charge condition
Condenser
Two-phase flow
Liquid flow
Appropriate condition
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2WAY VRF SYSTEM
2WAY VRF SYSTEM
Control Functions
Control Functions