Pump Down Residual Operation - Daikin SkyAir RZR-P Series Service Manual

Special Control
3.4

Pump Down Residual Operation

Pe: Low pressure sensor detection value
Td: Discharge pipe temperature
When activating compressor, if the liquid refrigerant remains in the heat-exchanger, the liquid
enters into the compressor and dilutes oil therein resulting in decrease of lubricity.
Therefore, the pump down residual operation is performed to collect the refrigerant in the heat-
exchanger when the compressor is down.
3.4.1 Pump Down Residual Operation in Cooling
Parts Name Symbol
Compressor

(INV.)
Outdoor unit

fan
Four way
20S1
valve
Electronic
expansion EV1
valve (Main)
Solenoid valve
SVP
(Hot gas)
Solenoid valve
(Receiver gas SVG
discharging)
Ending conditions
3.4.2 Pump Down Residual Operation in Heating
Parts Name Symbol
Compressor

(INV.)
Outdoor unit

fan
Four way
20S1
valve
Electronic
expansion EV1
valve (Main)
Solenoid valve
SVP
(Hot gas)
Solenoid valve
(Receiver gas SVG
discharging)
Ending conditions
Function and Control
Electric Symbol
RZR18/24/32P RZR36/42P
RZQ18/24/30P RZQ36/42P
M1C M1C
M1F
M1F
M2F
Y1S Y1S
Y1E Y1E
Y2S Y2S

Y3S
Electric Symbol
RZR18/24/32P RZR36/42P
RZQ18/24/30P RZQ36/42P
M1C M1C
M1F
M1F
M2F
Y1S Y1S
Y1E Y1E
Y2S Y2S

Y3S
Master unit operation
124 Hz
Fan control
OFF
2000 pls
OFF
ONOFF
 30 seconds
 Pe < 73 psi
OR
 Td > 230F
Master unit operation
124 Hz
STEP 8
ON
0 pls
OFF
ONOFF
 3 minutes
 Pe < 36 psi
OR
 Td > 230F
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