Daikin VRV III REYQ8PY1, Service Manual

Page: 131 / 452

Special Control Si37-701
120 Function
3.5 Pump-down Residual Operation
3.5.1 Pump-down Residual Operation in Cooling Operation
If the liquid refrigerant stays in the Evaporator at the startup of a compressor, this liquid refrigerant enters the
compressor, thus resulting in diluted oil in the compressor and then degraded lubrication performance.
Consequently, in order to recover the refrigerant in the Evaporator while the compressor stops, the pump-down residual
operation is conducted.
* Pe_min and Pc_max indicate the minimum and maximum values in the system, respectively.
Actuator Symbol
Elect.
symbol
Master unit operation Slave unit operation
REYQ REMQ
Compressor 1
—
M1C M1C
124 Hz+OFF+OFF OFF Compressor 2 M2C M2C
Compressor 3 M3C M3C
Outdoor unit fan 1
—
M1F M1F
Fan control Fan control
Outdoor unit fan 2 M2F M2F
Electronic expansion valve (Main) EVM
Y1E
Y3E
Y1E 1375 pls 1375 pls
Electronic expansion valve
(Supercooling)
EVT
Y2E
Y5E
Y3E 0 pls 0 pls
Electronic expansion valve
(Refrigerant charge)
EVJ Y4E Y2E 80 pls 80 pls
Four way valve (Heat exchanger
switch)
20SA
Y2S
Y9S
Y3S OFF OFF
Four way valve (High/low pressure
gas pipe switch)
20SB Y8S Y2S ON ON
Solenoid valve (Main bypass) SVE
Y5S
Y10S
Y6S ON ON
Solenoid valve (Hot gas) SVP Y4S Y5S OFF OFF
Solenoid valve (Refrigerant
regulator liquid pipe )
SVL Y3S Y4S OFF OFF
Solenoid valve (Refrigerant
regulator gas vent pipe)
SVG Y1S Y1S OFF OFF
Solenoid valve (Refrigerant
regulator exhaust pipe)
SVO Y7S Y7S OFF OFF
Solenoid valve (Refrigerant
regulator discharge pipe)
SVT Y6S Y8S OFF OFF
Ending conditions
•
5 min.
•
Pe_min<0.49 MPa
∗
•
Pc_max<2.94 MPa
∗
•
Master unit Tdi>110
°
C
•
Master unit Tp>125
°
C
or