2WAY VRF SYSTEM
Control Functions
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2
3
4
5
6
7
8
9
4. Special Control
2WAY VRF SYSTEM
Control Functions
Items
Remarks
Indication on PCB
This valve turns OFF at cooling mode, and turns ON at heating mode.
* When the outdoor unit stops, the 4-way valve maintains in the same state as before.
This valve turns OFF at defrosting control.
Solenoid valve
Expansion valve
Crankcase heater
4-way valve
Save valve
Refrigerant control valve
Refrigerant balance valve
Oil recovery valve
By-pass valve
Accumulator valve
O
2
valve
MOV for heat exchanger 1
MOV for heat exchanger 2
SC circuit expansion valve
Crankcase heater for 1st compressor
Crankcase heater for 2nd compressor
20S
SAVE
RCV
RBV
ORVR
BPV
ACV
O
2
MOV1
MOV2
MOV4
CH1
CH2
(1) 4-way Valve [20S]
This valve turns ON for 5 seconds before the inverter compressor starts. After the inverter compressor starts, the
valve is ON for 10 seconds. After that, it turns OFF.
SAVE valve
5 seconds
10 seconds
Inverter compressor starts
Compressor
(2) SAVE Valve [SAVE]
Valve turns ON
α
β
496.0 psi (3.42 MPa)
481.5 psi (3.32 MPa)
Valve turns OFF
This valve turns ON for 30 seconds after the outdoor unit stops. After that, it turns OFF.
This valve turns ON when the high pressure sensor detects α to prevent
abnormal pressure shown in the table at right.
This valve turns OFF when the high pressure goes down below β shown
in the table at right.
This valve turns ON when the high pressure switch is activated.
This valve stays ON for 10 seconds after the high pressure switch returns in normal.
After that, it turns OFF.
This valve might turn ON when the system capacity is excessive although the inverter compressor operates at
minimum frequency.
This valve turns ON while the discharge temperature of the compressor is low.
This valve turns ON during the operation of 4-way valve control.
4. Output of PCB
2WAY VRF SYSTEM
Control Functions
4. Special Control
(3) Refrigerant Control Valve [RCV]
The main purpose of this valve is to adjust the flow of refrigerant (refrigerant volume).
When the outdoor unit receives a sign of refrigerant shortage, the valve opens and refrigerant is supplied from the
receiver tank to the system.
This valve turns ON when the evaporator is refrigerant shortage.
The heat exchanger of indoor unit is the evaporator in cooling mode.
The heat exchanger of outdoor unit is the evaporator in heating mode.
This valve turns OFF when the excessive amount of refrigerant is in the condenser.
The heat exchanger of indoor unit is the condenser in heating operation.
The heat exchanger of outdoor unit is the condenser in cooling operation.
This valve turns OFF when the outdoor unit is stopped.
This valve might turn ON when a special control is in progress.
Evaporator
RBV
RCV
LP
HP
Refrigerant shortage in evaporator.
Receiver tank holds refrigerant.
Two-phase
flow
Evaporator
RBV
RCV
LP
HP
Sufficient refrigerant is supplied to evaporator.
High pressure from RCV pushes the liquid refrigerant out of the receiver tank.
ON
Two-phase flow
SM830237-07_北米向け2WAY_VRF.indb 13
18/06/19 18:55:31