Startup Control; Startup Control In Cooling - Daikin VRV RXYQ72-384XAYCA Service Manual

Startup Control

4. Startup Control
This control is used to equalize the pressure in the suction and discharge sides of the compressor
prior to the startup of the compressor, thus reducing startup loads. Furthermore, the inverter is
turned ON to charge the capacitor.
To avoid stresses to the compressor due to oil return or else after the startup, the following control
is made and the position of the four way valve is also determined. Start both the master and the
slave units simultaneously to position the four way valve.
4.1

Startup Control in Cooling

Compressor
(M1C)
0 pulse
Electronic expansion
valve (main)
(Y1E)
Step 15
Fan motor
(M1F + M2F)
Pc – Pe > 0.17 MPa (24.7 psi)
DSH : Discharge pipe superheating degree
Pc : High pressure sensor detection value
Pe : Low pressure sensor detection value
Ta : Outdoor air temperature
Reference
Refer to page 93 for Step X.
85
Frequency step up
5 sec. interval
E
D
C
B
A
0 Hz
3,000 pulse (fully open)
Ta < 20°C: OFF
(68°F)
+3step/15 sec. (Pc > 2.16 MPa (313 psi))
Ta  20°C: StepX/2
–3step/15 sec. (Pc < 1.77 MPa (257 psi))
(68°F)
Frequency
(rps)
A
B
C
D
E
Pc – Pe > 0.42 MPa (60.9 psi)
Pc – Pe > 0.32 MPa (46.4 psi)
&
OR
20 rps or more
DSH > 10°C (18°F)
SiUS342004EB
RXYQ72-120XA RXYQ144/168XA
RXYQ72-120XB RXYQ144/168XB
19 16.4
24 16.4
29 18
38 24
57 36
Part 4 Functions and Control