Daikin SkyAir FHQ24PVJU - Pump down Residual Control

SiUS281811EA Special Control
Part 4 Functions and Control 115
3.4 Pump Down Residual Control
If liquid refrigerant is retained in the evaporator when the compressor is activated, the liquid
refrigerant enters the compressor and dilutes oil therein resulting in a decrease of lubricity.
Therefore, pump down residual control is performed to collect the refrigerant retained in the
evaporator when the compressor stops.
3.4.1 Pump Down Residual Control in Cooling
3.4.2 Pump Down Residual Control in Heating
Outdoor unit actuator
Electric Symbol
Pump down residual control:
Step 1
Pump down residual control:
Step 2
18/24
class
30/36/42/48
class
Compressor M1C M1C 124 Hz Minimum frequency
Outdoor fan M1F M1F
M2F
Fan control Fan control
Main electronic
expansion valve
Y1E Y1E 480 pulse (Fully open) 240 pulse (Half open)
Subcooling electronic
expansion valve
— Y3E 0 pulse 0 pulse
Four way valve Y1S Y1S OFF OFF
Hot gas bypass valve Y2S — OFF OFF
Ending conditions 2 seconds 2 seconds
Outdoor unit actuator
Electric Symbol
Pump down residual control
18/24
class
30/36/42/48
class
Compressor M1C M1C 124 Hz
Outdoor fan M1F M1F
M2F
STEP 7
Main electronic
expansion valve
Y1E Y1E 0 pulse
Subcooling electronic
expansion valve
— Y3E 0 pulse
Four way valve Y1S Y1S ON
Hot gas bypass valve Y2S — OFF
Ending conditions 4 seconds