Special Control; Startup Control - Daikin ALTHERMA HT ERSQ 011 AA Service Manual

Special Control

3. Special Control

Startup Control

3.1
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 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 Heating Operation
Outdoor
Compressor
Outdoor unit fan
Four way valve
Main electronic expansion
valve (EV1)
Subcooling electronic
expansion valve (EV3)
Hot gas bypass valve (SVP)
Ending conditions
Indoor
Indoor compressor
4-way valve
Pump
* Always after POWER ON/OFF, compressor frequency is limited. This is not the case after thermo ON/OFF/ON.
Remark: A thermostat ON demand will activate the outdoor fan, followed by the outdoor compressor and finally indoor
compressor.
58
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.
STEP1
First 10 minutes -> maximum 128 Hz*
OFF
HOT START
 High pressure side > 14 bar
OR
 Maximum 5 minutes

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
To maximum frequency
OFF
Gradual to PI control
ESIE09-08A
STEP2
 A lapse of 130 sec.
 Pc>2.70MPa
 Pc - Pe>0.39MPa
STEP2
Function