SiUS30-1301
Startup Control
Function and Control
49
4.3
Pressure Equalizing Control
This pressure equalizing control is used to equalize the pressure of discharge piping and suction
piping in order to reduce refrigerant passing noise when changing over the Branch Selector units.
[Starting conditions]
The temperature control of indoor units with thermostat ON does not match up with the state of the
Branch Selector unit changeover valve to which the indoor units are connected.
Parts name
Symbol
Electric symbol
Pressure equalizing control
Inverter compressor
—
M1C
74Hz
Four way valve (Main)
20S1
Y5S
OFF
Four way valve (Sub)
20S2
Y7S
OFF
Electronic expansion valve (Main)
EV1
Y1E
2000 pulse
Electronic expansion valve (Subcooling)
EV3
Y3E
0 pulse
Solenoid valve (Hot gas)
SVP
Y1S
ON
Solenoid valve (Oil return of water heat
exchanger)
SVE
Y2S
OFF
Solenoid valve (Receiver gas charging)
SVL
Y3S
OFF
Solenoid valve (Receiver gas
discharging)
SVG
Y4S
OFF
Solenoid valve (Non-operating unit liquid
pipe closing)
SVSL
Y6S
ON
Indoor unit fan (Cooling)
—
M1F, M2F
No instruction
Indoor unit electronic expansion valve
(Cooling)
EV
Y1E
No instruction
Indoor unit fan (Heating)
—
M1F, M2F
OFF
Indoor unit electronic expansion valve
(Heating)
EV
Y1E
192 pulse
Ending condition
Max. 5 minutes