Special Control - Daikin RQYQ140-180PY1 Service Manual

SiBE341001
2.7

Special Control

2.7.1 Pump-down Residual 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.
Electric
Part Name
Symbol
Compressor M1C
Outdoor unit fan M1F
Electronic expansion
Y1E
valve (Main)
Electronic expansion
valve (Refrigerant Y2E
charge)
Electronic expansion
Y3E
valve (Subcooling)
Solenoid valve
(Refrigerant regulator Y1S
hot gas)
Solenoid valve
(Refrigerant regulator Y2S
liquid pipe)
Solenoid valve
(Refrigerant regulator Y3S
gas vent pipe)
Solenoid valve (Hot
Y4S
gas)
Solenoid valve
Y5S
(Circuit of oil return)
Four way valve (Heat
Y6S
exchanger switch)
Four way valve (Dual
Y7S
pressure gas pipe)
Four way valve
Y8S
(Mixing unit)
Solenoid valve
Y9S
(Mixing unit inlet)
Ending condition
Function
Normal Cooling
Master Unit Slave Unit
124 Hz
Fan control Fan control
480 pls
0 pls
0 pls
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
• 5 min. passed
• Pe_min<0.49MPa
• Pc_max>2.94MPa
OR
• Master unit Tdi > 110°C
• Master unit Tp > 125°C
Normal Simultaneous Cooling / Heating
Master Unit
OFF 124 Hz
Fan control
Four way valve "ON":
0 pls
0 pls
Four way valve
"OFF": 480 pls
0 pls 0 pls
0 pls 0 pls
OFF OFF
OFF OFF
OFF OFF
OFF OFF
OFF OFF
OFF OFF
OFF OFF
OFF OFF
OFF OFF
OR
Detailed Control Functions
Slave Unit
OFF
Fan control
Four way valve "ON":
0 pls
Four way valve
"OFF": 480 pls
0 pls
0 pls
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
• 3 min. passed
• Pe_min<0.25MPa
• Pc_max>3.13MPa
• Master unit Tdi > 110°C
• Master unit Tp > 140°C
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