Pump-Down Residual Operation - Daikin REYQ72 Serveice Manual

Special Control
3.5

Pump-down Residual Operation

If any liquid refrigerant remains in the heat exchanger during compressor startup, the liquid
refrigerant will enter the compressor, resulting in the dilution of the refrigerating machine oil in
the compressor and the degradation of lubricating capacity.
Therefore, before the compressor stops, pump-down operation is performed to collect the
refrigerant in the heat exchanger.
3.5.1 Pump-down Residual Operation in Cooling Operation
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)
Discharge pipe stop valve (SVR)
Non-operating unit liquid pipe stop valve (SVSL)
High pressure gas pipe pressure reduction
valve (SVC)
Ending conditions
Indoor unit EV opening
54
Actuator Operation
210 Hz + OFF
Fan control
OFF
OFF
1400 pls
1400 pls
0 pls
ON
ON
OFF
OFF
OFF
OFF
OFF
• 5 min.
• Pe < 72.5 psi
or
• Td > 230°F
0 pls
SiUS39-602
Function