Pressure Equalizing Control - Daikin REYQ72 Serveice Manual

SiUS39-602
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
Compressor
Outdoor unit fan
Four way valve 1
Four way valve 2
Main motorized valve (EV1)
Sub motorized valve (EV2)
Sub-cooling motorized valve (EV3)
Hot gas bypass valve (SVP)
Oil equalization valve (SVO)
Receiver gas charging valve (SVL)
Receiver gas discharge valve (SVG) OFF
Discharging gas pipe stop valve
(SVR)
Non-operating unit liquid pipe stop
valve (SVSL)
High pressure gas pipe pressure
reduction valve (SVC)
Ending conditions
Function
Pressure equalizing
preparation operation
PI control
Depend on previous heat
exchange mode
Depend on previous heat
exchange mode
Depend on previous heat
exchange mode
Four way valve 1
OFF:1400 pls
ON:SH control
Four way valve 2
OFF:1400 pls
ON:SH control
0 pls
OFF
ON
OFF
ON
ON
OFF
2 min.
Equalization operation
74 Hz + OFF
STEP7
ON
OFF
180 pls
1400 pls
0 pls
OFF
ON
OFF
OFF
OFF
ON
ON
• 200 sec.
or
• Pc - Pe>58 psi
Special Control
53