Midea V4 Plus S Series Service Manual page 38

R410A All DC Inverter V4+S Series 60Hz
14-16HP
DC Fan
Heat Exchanger
High Pressure
HPS
Switch
14~16HP
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
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
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.
36
SV6
EXV B
ST 1
High
Pressure
Sensor
SENP
SV4
ST1
2.2x1.1x2500
Ф
18HP
EXV A
SV5
Low Pressure
SV2
Receiver
Low
Pressure
Switch
LPS
SV6
EXVA
EXVB
SV5
SV2
2.0
Ф
o
C.
MCAC-VTSM-2015-09
SV1
3.2x1.9x1000
Ф
Specifications & Performances
Stop Valve
(High Pressure)
Stop Valve
(Low Pressure)
Oil Balance
o
C,