Startup Control; Startup Control In Cooling Operation - Daikin RTSQ20PY1 Service Manual

Startup Control

5. 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.
In addition, to avoid stresses to the compressor due to liquid refrigerant return or else after the startup, the following
control is made and the position of the four way valve is also determined. To position the four way valve, the master and
slave units simultaneously start up.
5.1

Startup Control in Cooling Operation

Actuator
Compressor 1
Compressor 2
Compressor 3
Outdoor unit fan 1
Outdoor unit fan 2
Electronic expansion
valve (Main)
Electronic expansion
valve (Subcooling)
Electronic expansion
valve (Refrigerant
charge)
Solenoid valve
(Refrigerant regulator gas
purging pipe)
Four way valve
(Heat exchanger switch)
Solenoid valve
(Refrigerant regulator
liquid pipe)
Solenoid valve (Hot gas)
Solenoid valve (Main
bypass)
Solenoid valve
(Refrigerant regulator
discharge pipe)
Solenoid valve
(Refrigerant regulator
discharge pipe)
Four way valve (High/low
pressure gas pipe switch) 20SB
Ending conditions
87
Pressure
Elect. equalization
Symbol
symbol control
before startup
M1C
— M2C 0 Hz
M3C
M1F
— STEP4
M2F
EVM Y1E 0 pls
EVT Y3E 0 pls
EVJ Y2E 80 pls
SVG Y1S OFF
20SA Y3S OFF
SVL Y4S OFF
SVP Y5S OFF
SVE Y6S OFF
SVO Y7S OFF
SVT Y8S OFF
Y2S ON
A lapse of 60
sec.
Startup control
STEP1
52 Hz+OFF+OFF
Ta<20°C: OFF
Ta≥20°C: STEP4
480 pls
0 pls
80 pls
OFF
OFF
OFF
OFF
ON
OFF
OFF
ON
A lapse of 15 sec.
SiBE31-801_C
STEP2
52Hz+OFF+OFF+2STEP / 20
sec.
(Until it reaches
Pc-Pe>0.39 MPa)
+1step/15 sec. (When
Pc_max>2.16 MPa)
-1step/15 sec. (When
Pc_max<1.77 MPa)
480 pls
0 pls
80 pls
OFF
OFF
OFF
OFF
ON
OFF
OFF
ON
• A lapse of 90 sec.
OR
• Pc - Pe>0.39 MPa
Function