Daikin VRVIII-S, Service Manual

Page: 56 / 266

SiENBE34-703 Special Control
Function 45
3. Special Control
3.1 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 oil 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.
3.1.1 Startup Control in Cooling Operation
3.1.2 Startup Control in Heating Operation
Thermostat ON
Pressure equalization control
prior to startup
Startup control
STEP1 STEP2
Compressor 0 Hz 57 Hz Unload
57 Hz Unload
+2 steps/20 sec.
(until Pc - Pe>0.39MPa is achieved)
Outdoor unit fan STEP7
Ta<20
°
C: OFF
Ta
≥
20
°
C: STEP4
+1 step/15 sec. (when Pc>2.16MPa)
-1 step/15 sec. (when Pc<1.77MPa)
Four way valve (20S1) Holds OFF OFF
Main electronic expansion
valve (EV1)
0 pls 480 pls 480 pls
Subcooling electronic
expansion valve (EV3)
0 pls 0 pls 0 pls
Hot gas bypass valve
(SVP)
OFF OFF OFF
Ending conditions
•
Pc - Pe<0.3MPa
•
A lapse of 1 to 5 min.
A lapse of 10 sec.
•
A lapse of 130 sec.
•
Pc - Pe>0.39MPa
OR OR
Thermostat ON
Pressure equalization control
prior to startup
Startup control
STEP1 STEP2
Compressor 0 Hz 57 Hz Unload
57 Hz Unload
+2 steps/20 sec.
(until Pc - Pe>0.39MPa is achieved)
Outdoor unit fan
From starting
~ 1 min. : STEP 7
1 ~ 3 min. : STEP 3
3 ~ 5 min. : OFF
STEP8 STEP8
Four way valve Holds ON ON
Main electronic expansion
valve (EV1)
0 pls 0 pls 0 pls
Subcooling electronic
expansion valve (EV3)
0 pls 0 pls 0 pls
Hot gas bypass valve
(SVP)
OFF OFF OFF
Ending conditions
•
Pc - Pe<0.3MPa
•
A lapse of 1 to 5 min.
A lapse of 10 sec.
•
A lapse of 130 sec.
•
Pc>2.70MPa
•
Pc - Pe>0.39MPa
OR OR