R410A All DC Inverter V4+S Series 60Hz      MCAC-VTSM-2015-09 
36 Specifications & Performances 
14-16HP 
Oil Balance
Stop Valve
(Low Pressure)
Stop Valve
(High Pressure)
Compressor
 INVERTER
Compressor
INVERTER
Oil Separator
unloading valve
SV4
Heat Exchanger
DC Fan
EXV A
SV6
SV5
ST 1
EXV B
SV2
Low Pressure
Receiver
14~16HP
LPS
Low
Pressure
Switch
HPS
High Pressure
Switch
SENP
High
Pressure
Sensor
 
18HP 
SV2
ST1
SV5
SV6
EXVA
Ф3.2x1.9x1000
Ф2.5x1.5x1500
Ф2.2x1.1x2500
SV4
Ф2.0
EXVB
SV1
18HP
 
Key components: 
Oil separator: It is used to separate oil from high pressure and high temperature gas refrigerant, which is 
pumped out from compressor. The separation efficiency is up to 99%, it makes the oil return back to each 
compressor very soon. 
Gas-liquid separator: It is used to store the liquid refrigerant and oil; it can protect the compressor from liquid 
hammering. 
EXV (Electronic Expansion Valve): It is used to adjust refrigerant volume. 
Four-way valve  ST1:  Closed in  cooling mode and  open  in heating mode.  The  four-way  valve is  used  to 
change the refrigerant flow direction in heating mode. When the ST1 is OFF, the heat exchanger functions as a 
condenser. When the ST1 is ON, the heat exchanger functions as an evaporator. 
SV2: It is used to protect the compressor. When any compressor discharge temperature is higher than 100
o
C, 
SV2 will be open and spray a small amount of liquid refrigerant to cooling compressor, and it will be closed 
when the discharge temperature is lower than 90
o
C. 
SV4: Oil return valve. Opens after the inverter compressor has run for 5 minutes and will close 15 minutes later 
(for single outdoor unit system).   
Every 20 minutes, the SV4 of each outdoor unit will open for 3 minutes (for multiple outdoor unit system). 
SV5: It is used for fast defrosting. In defrosting mode, the opening of SV5 can shorten the refrigerant flowing 
circle, so the defrosting process will takes less time. In cooling mode, it is always off.   
SV6: It is used for by-pass. Open when the discharge temperature is over-high in cooling mode, and close 
when the unit is standby or system is in heating mode. 
Pressure switch: It is used to protect the system pressure. When the system pressure is too high or too low, 
the pressure switch will open. Once the pressure switch is open, the compressor will stop, and the compressor 
will restart after ten minutes.