Pump-Down Residual Operation - Daikin ERQ Service Manual

Special Control
3.4

Pump-down Residual Operation

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 Operation
Actuator
Compressor
Outdoor unit fan
Four way valve
Main electronic expansion valve (EV1)
Subcooling electronic expansion valve
(EV3)
Hot gas bypass valve (SVP)
Ending conditions
3.4.2 Pump-down Residual Operation in Heating Operation
Actuator
Compressor
Outdoor unit fan
Four way valve
Main electronic expansion valve (EV1)
Subcooling electronic expansion valve
(EV3)
Hot gas bypass valve (SVP)
Ending conditions
30
Pump-down residual operation Step 1
124 Hz Full load
Fan control
OFF
480 pls
0 pls
OFF
2 sec.

Pump-down residual operation

124 Hz Full load
STEP7
ON
0 pls
0 pls
OFF
4 sec.
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Pump-down residual operation Step 2
52 Hz Full load
Fan control
OFF
240 pls
0 pls
OFF
2 sec.
ESIE09-05
Function