Pump-Down Residual Operation - Daikin VRV III REYQ8PY1 Service Manual

Special Control
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.
Actuator
Compressor 1
Compressor 2
Compressor 3
Outdoor unit fan 1
Outdoor unit fan 2
Electronic expansion valve (Main) EVM
Electronic expansion valve
(Supercooling)
Electronic expansion valve
(Refrigerant charge)
Four way valve (Heat exchanger
switch)
Four way valve (High/low pressure
gas pipe switch)
Solenoid valve (Main bypass)
Solenoid valve (Hot gas)
Solenoid valve (Refrigerant
regulator liquid pipe )
Solenoid valve (Refrigerant
regulator gas vent pipe)
Solenoid valve (Refrigerant
regulator exhaust pipe)
Solenoid valve (Refrigerant
regulator discharge pipe)
Ending conditions
* Pe_min and Pc_max indicate the minimum and maximum values in the system, respectively.
120
Elect.
symbol
Symbol
REYQ REMQ
M1C M1C
— M2C M2C 124 Hz+OFF+OFF
M3C M3C
M1F M1F
— Fan control
M2F M2F
Y1E
Y1E 1375 pls
Y3E
Y2E
EVT Y3E 0 pls
Y5E
EVJ Y4E Y2E 80 pls
Y2S
20SA Y3S OFF
Y9S
20SB Y8S Y2S ON
Y5S
SVE Y10S Y6S ON
SVP Y4S Y5S OFF
SVL Y3S Y4S OFF
SVG Y1S Y1S OFF
SVO Y7S Y7S OFF
SVT Y6S Y8S OFF
or
Master unit operation
• 5 min.
• Pe_min<0.49 MPa ∗
• Pc_max<2.94 MPa ∗
• Master unit Tdi>110°C
• Master unit Tp>125°C
Si37-701
Slave unit operation
OFF
Fan control
1375 pls
0 pls
80 pls
OFF
ON
ON
OFF
OFF
OFF
OFF
OFF
Function