Special Control; Startup Control; Siau18 - Daikin E-Series Service Manual

SiAU18-715

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
Compressor
Outdoor unit fan
Four way valve (20S1)
Main electronic expansion
valve (EV1)
Subcooling electronic
expansion valve (EV3)
Hot gas bypass valve
(SVP)
Ending conditions
3.1.2 Startup Control in Heating Operation
Compressor
Outdoor unit fan
Four way valve
Main electronic expansion
valve (EV1)
Subcooling electronic
expansion valve (EV3)
Hot gas bypass valve
(SVP)
Ending conditions
Function
Thermostat ON
Pressure equalization control
prior to startup
0 Hz
STEP7
Holds
0 pls
0 pls
OFF
• Pc - Pe<0.3MPa
OR
• A lapse of 1 to 5 min.
Thermostat ON
Pressure equalization control
prior to startup
0 Hz
From starting
~ 1 min. : STEP 7
1 ~ 3 min. : STEP 3
3 ~ 5 min. : OFF
Holds
0 pls
0 pls
OFF
• Pc - Pe<0.3MPa
OR
• A lapse of 1 to 5 min.

Startup control

STEP1
57 Hz Unload
57 Hz Unload +2 steps/20 sec.
(until Pc - Pe>0.39MPa is achieved)
Ta<20°C: OFF +1 step/15 sec. (when Pc>2.16MPa)
Ta≥20°C: STEP4 -1 step/15 sec. (when Pc<1.77MPa)
OFF OFF
480 pls 480 pls
0 pls 0 pls
OFF OFF
A lapse of 10 sec. OR
Startup control
STEP1
57 Hz Unload
57 Hz Unload +2 steps/20 sec.
(until Pc - Pe>0.39MPa is achieved)
STEP8 STEP8
ON ON
0 pls 0 pls
0 pls 0 pls
OFF OFF
A lapse of 10 sec. OR

Special Control

STEP2
• A lapse of 130 sec.
• Pc - Pe>0.39MPa
STEP2
• A lapse of 130 sec.
• Pc>2.70MPa
• Pc - Pe>0.39MPa
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