Specifications

SiUS39-602 Special Control
Function 53
3.4 Pressure Equalizing Control
This pressure equalization control is used to equalize the pressure of discharge piping and
suction piping in order to reduce refrigerant passing noise when changing over the BS units.
[Starting conditions]
The temperature control of indoor units with thermostat ON does not match up with the state of
the BS unit changeover valve to which the indoor units are connected.
Actuator
Pressure equalizing
preparation operation
Equalization operation
Compressor PI control 74 Hz + OFF
Outdoor unit fan
Depend on previous heat
exchange mode
STEP7
Four way valve 1
Depend on previous heat
exchange mode
ON
Four way valve 2
Depend on previous heat
exchange mode
OFF
Main motorized valve (EV1)
Four way valve 1
OFF:1400 pls
ON:SH control
180 pls
Sub motorized valve (EV2)
Four way valve 2
OFF:1400 pls
ON:SH control
1400 pls
Sub-cooling motorized valve (EV3) 0 pls 0 pls
Hot gas bypass valve (SVP) OFF OFF
Oil equalization valve (SVO) ON ON
Receiver gas charging valve (SVL) OFF OFF
Receiver gas discharge valve (SVG) OFF OFF
Discharging gas pipe stop valve
(SVR)
ON OFF
Non-operating unit liquid pipe stop
valve (SVSL)
ON ON
High pressure gas pipe pressure
reduction valve (SVC)
OFF ON
Ending conditions 2 min.
• 200 sec.
• Pc - Pe>58 psi
or