2WAY VRF SYSTEM
Control Functions
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4. Special Control
2WAY VRF SYSTEM
Control Functions
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.
(4) Refrigerant Balance Valve [RBV]
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.
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).
Condenser
RBV
RCV
LP
HP
Over charge condition
Receiver tank holds a low refrigerant volume.
Two-phase flow
Liquid flow
Condenser
RBV
RCV
LP
HP
Appropriate condition
Refrigerant gas in the top of receiver tank is absorbed into low pressure side.
ON
Two-phase flow
Liquid flow
2WAY VRF SYSTEM
Control Functions
4. Special Control
(5) Oil Recovery Valve [ORVR]
The purpose of this valve is to recover oil from the oil separator of its own outdoor unit or balance tube to the
compressor.
This valve turns ON when the oil level of the compressor is “0” or “1”.
This valve turns ON for 2 minutes after the compressor starts.
This valve is always OFF when outdoor unit is stopped.
* For oil level of compressor, see “7. Oil Control”.
This valve turns ON when recovering refrigerant from the stopped outdoor unit.
(6) By-pass Valve [BPV]
This valve is for pushing the oil in the balance piping into other outdoor units.
When the compressor oil level of its own outdoor unit is in the “2” or “1”, this valve turns ON when the oil level “0”
is detected in other outdoor units.
When the compressor itself is stopped with a full of refrigerant, this valve turns ON.
Then the refrigerant is supplied to the other operating outdoor units.
* This valve turns ON for 10 seconds and turns OFF for 20 seconds.
This operation is repeated while oil is supplied to others.
* For more information on oil level of compressor, see “7. Oil Control”.
(7) Accumulator Valve [ACV]
The purpose of this valve is to recover oil and refrigerant from the accumulator
to the compressor.
This valve turns OFF when the compressor operation just started.
This valve turns ON when the compressor is warmed up.
This valve turns ON while the oil recovery among the systems and defrost
control are in progress.
This valve turns ON while the MOV4 is operating.
(8) O
2
Valve [O
2
*]
ACV
Accumulator
This valve works when the outdoor unit receives signal of the refrigerant leakage from the indoor unit.
*O
2
valve is the field supply parts.
The indoor unit that transmits the signal of the refrigerant leakage gives “P14”alarm.
To activate this function, it is necessary to set it to EEPROM on the main outdoor PCB and indoor PCB.
EEPROM setting in main outdoor unit
CODE: C1
Setting No
Setting No
0
0
1
1
2
This function invalid (factory preset mode)
This valve is turned OFF when the system is normal.
This valve is turned ON when the outdoor unit receives signal from the indoor unit
This valve is turned ON when the system is normal.
This valve is turned OFF when the outdoor unit receives signal from the indoor unit
EEPROM setting in indoor unit
CODE: 0B
Function of EXCT plug short-circuit
Indoor unit does thermostat OFF
(factory preset mode)
Indoor unit gives “P14”alarm and transmits the refrigerant leakage signal.
4. Output of PCB
SM830237-07_北米向け2WAY_VRF.indb 15
18/06/19 18:55:31
