Special Control; Pump Down Residual Operation - Daikin VRV EMERION REYQ-AATJA Service Manual

Special Control

7. Special Control
7.1

Pump Down Residual Operation

If the liquid refrigerant stays in the evaporator at the startup of a compressor, this liquid refrigerant
enters the compressor, thus resulting in diluted oil in the compressor and then degraded lubrication
performance.
Consequently, in order to recover the refrigerant in the evaporator while the compressor stops, the
pump down residual operation is conducted.
Pc: High pressure sensor detection value
Pe: Low pressure sensor detection value
Ta: Outdoor air temperature
Te: Low pressure equivalent saturation temperature
DSH: Discharge pipe superheating degree
Part name
Compressor motor
Fan motor
Electronic expansion valve
(Heat exchanger right upper)
Electronic expansion valve
(Heat exchanger right lower)
Electronic expansion valve
(Heat exchanger left)
Electronic expansion valve
(Subcooling heat exchanger)
Electronic expansion valve
(Receiver gas purge)
Electronic expansion valve
(Refrigerant cooling IPM)
Electronic expansion valve
(Refrigerant cooling air)
Solenoid valve
(Oil separator oil return)
Solenoid valve (Liquid shutoff)
Solenoid valve
(Accumulator oil return)
Solenoid valve
(Refrigerant adjustment)
Solenoid valve (Injection)
Four way valve
(Heat exchanger right upper)
Four way valve
(Heat exchanger right lower)
Four way valve
(Heat exchanger left)
Four way valve (HP/LP gas pipe)
Solenoid valve
(Refrigerant cooling bypass)
Ending condition
165
Electric symbol
REYQ72/192/216/240AA: 25 rps
M1C, M2C
REYQ96/120/144/168AA: 37 rps
M1F, M2F For heat exchanger mode
Same as normal control
Y1E
Y2E
Y5E
0 pulse
Y3E
Open slightly
Y4E
Same as normal control
Y6E
Y7E
ON
Y1S, Y2S
Y3S ON
OFF
Y4S
OFF
Y5S
Y6S ON
Hold
Y10S
Y7S
Y9S
Y8S
Same as normal control
Y11S
A lapse of 2 minutes
OR Master unit HTdi > 118qC (244.4°F)
Pc_max > 2.94 MPa (426 psi)
Function of functional part
Cooling
REYQ72/192/216/240AA: 80 rps
REYQ96/120/144/168AA: 75 rps
For heat exchanger mode
Same as normal control
0 pulse
Open slightly
Same as normal control
ON
ON
OFF
OFF
ON
Hold
Same as normal control
OR
SiUS372201EB
Heating
A lapse of 3 minutes
Pe_min < 0.19 MPa (27.6 psi)
&
Ta_min – Te_max > 8qC (14°F)
HTdi_max > 118qC (244.4°F)
Part 4 Functions and Control