Daikin RXSQ24TAVJU, Service Manual, Page: 63 / 311

SiUS331708EA Special Control
Functions and Control 50
3.4 Pump Down Residual Operation
When activating the compressor, if liquid refrigerant remains in the evaporator, the liquid enters the compressor
and dilutes oil therein resulting in a decrease in lubricity.
Therefore, pump down residual operation is performed to collect refrigerant in the evaporator when the
compressor is stopped.
3.4.1 Pump Down Residual Operation in Cooling
3.4.2 Pump Down Residual Operation in Heating
Outdoor unit actuator
Electric symbol
Pump down residual operation:
Step 1
Pump down residual operation:
Step 2
24/36 class 48 class 60 class
Compressor M1C M1C M1C
STEP 18 load (24/36 class)
58 rps (48/60 class) STEP 6 load (24/36 class)
24 rps (48/60 class)
Outdoor fan M1F M1F
M1F,
M2F
Fan control Fan control
Four way valve Y1S Y1S Y1S OFF OFF
Main electronic expansion
valve
Y1E Y1E Y1E 480 pulse (Fully open)
240 pulse (Half open) (24/36 class)
480 pulse (Fully open) (48/60 class)
Subcooling electronic
expansion valve
 
Y3E 0 pulse 0 pulse
Hot gas bypass valve Y2S
 
OFF OFF
Injection valve Y3S Y3S

OFF OFF
Ending conditions 2 seconds 2 seconds
Outdoor unit actuator
Electric symbol
Pump down residual operation
24/36 class 48 class 60 class
Compressor M1C M1C M1C
STEP 18 load (24/36 class)
STEP 9 load (48/60 class)
Outdoor fan M1F M1F
M1F,
M2F
STEP 7
Four way valve Y1S Y1S Y1S ON
Main electronic expansion
valve
Y1E Y1E Y1E 0 pulse
Subcooling electronic
expansion valve
 
Y3E 0 pulse
Hot gas bypass valve Y2S
 
OFF
Injection valve Y3S Y3S

OFF
Ending conditions
4 seconds (24/36 class)
Up to 3 minutes (48/60 class)