Startup Control; Startup Control In Cooling - Daikin RXYQ-TA Series Service Manual

SiUS341615E

4. Startup Control

This control is used to equalize the pressure in the front and back 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

Inverter compressor 1
(M1C)
Inverter compressor 2
(M2C)
∗ RXYQ144/168TA only
Electronic expansion
valve (main)
(Y1E)
Inverter fan
M1F: RXYQ72TA
M1F + M2F: RXYQ96-168TA
Pc : High pressure sensor detection value
Pe : Low pressure sensor detection value
Ta : Outdoor air temperature
Te : Low pressure equivalent saturation temperature
Functions and Control
Frequency step up
5 sec. interval
E
D
C
B
A
0 Hz
0 Hz
3,000 pulse (fully open)
0 pulse
Ta < 20˚C: OFF
(68˚F)
Ta ≥ 20˚C: Step4
+1step/15 sec. (Pc > 2.16 MPa (313 psi))
–1step/15 sec. (Pc < 1.77 MPa (257 psi))
Step 4 (68˚F)
Pc – Pe > 0.17 MPa (24.7 psi)
Frequency
(Hz)
RXYQ144/168TA
A
B
C
D
E
Pc – Pe > 0.78 MPa (113 psi)
OR
Pc – Pe > 0.39 MPa (56.6 psi)
&
164 Hz or more
Startup Control
RXYQ72TA
RXYQ96/120TA
52 60
74 75
90 90
120 120
164 180
54