Special Control; Startup Control - Daikin RMXS-L Series Service Manual

Special Control

3. Special Control
3.1

Startup Control

Startup control equalizes the pressure in the front and back of the compressor before 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 operation, etc. after 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 fan
Four way valve (Y1S)
Main electronic expansion
valve (Y1E)
Subcooling electronic
expansion valve (Y3E)
Hot gas bypass solenoid
valve (Y2S)
Ending conditions
3.1.2 Startup Control in Heating Operation
Compressor
Outdoor fan
Four way valve (Y1S)
Main electronic expansion
valve (Y1E)
Subcooling electronic
expansion valve (Y3E)
Hot gas bypass solenoid
valve (Y2S)
Ending conditions
56
Thermostat ON
Pressure equalization control
before startup
0 Hz
STEP 7
Holds
0 pulse
0 pulse
OFF
• Pc – Pe < 0.3 MPa
or
(100 ftAq)
• A lapse of 1 to 5 min.
Thermostat ON
Pressure equalization control
before startup
0 Hz
From starting
~ 1 min. : STEP 7
1 ~ 3 min. : STEP 3
3 ~ 5 min. : OFF
Holds
0 pulse
0 pulse
OFF
• Pc – Pe < 0.3 MPa
or (100 ftAq)
• A lapse of 1 to 5 min.
Startup control
STEP 1
57 Hz Unload
57 Hz Unload +2 steps / 20 sec.
(until Pc – Pe > 0.39 MPa (130 ftAq))
Ta < 20°C: OFF +1 step / 15 sec.
(68°F) (when Pc > 2.16 MPa (723 ftAq))
Ta ≥ 20°C: STEP 4
–1 step / 15 sec.
(68°F) (when Pc < 1.77 MPa (592 ftAq))
OFF OFF
480 pulse 480 pulse
0 pulse 0 pulse
OFF OFF
or
A lapse of 10 sec.
Startup control
STEP 1
57 Hz Unload
57 Hz Unload +2 steps / 20 sec.
(until Pc – Pe > 0.39 MPa (130 ftAq))
STEP 8 STEP 8
ON ON
0 pulse 0 pulse
0 pulse 0 pulse
OFF OFF
A lapse of 10 sec. or
SiUS181631EA
STEP 2
• A lapse of 130 sec.
• Pc – Pe > 0.39 MPa
(130 ftAq)
STEP 2
• A lapse of 130 sec.
• Pc > 2.70 MPa (903 ftAq)
• Pc – Pe > 0.39 MPa (130 ftAq)
Functions and Control