Special Control; Startup Control - Daikin RXSQ24TAVJU Service Manual

Special Control

3. Special Control
3.1

Startup Control

This control is used to equalize the pressure in the suction and discharge sides of the compressor prior to
compressor startup, 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, etc., after startup, the following control is made
and the position of the four way valve is also determined.
Pc : High pressure sensor detection value
Pe : Low pressure sensor detection value
Ta : Outdoor air temperature
Tc : High pressure equivalent saturation temperature
3.1.1 Startup Control in Cooling Operation
Electric symbol
Outdoor unit
actuator
24/36 class 48 class 60 class
Compressor M1C
Outdoor fan M1F
Four way valve Y1S
Main electronic
Y1E
expansion valve
Subcooling

electronic
expansion valve
Hot gas bypass
Y2S
valve
Injection valve Y3S
Ending conditions
45
Thermostat ON
Pressure equalization control
prior to startup
M1C M1C 0 Hz
M1F,
M1F OFF
M2F
Y1S Y1S Holds
Y1E Y1E 0 pulse

Y3E 0 pulse
 
ON

Y3S OFF
• Pc – Pe < 0.3 MPa
OR
(43.5 psi)
• A lapse of 5 min.
Startup control
STEP 1
Increases 2 steps every 20 seconds
from minimum frequency
Minimum frequency
until Pc – Pe > 0.39 MPa
(56.6 psi) is achieved
Ta < 20°C (68°F): +1 step/15 sec. (when Pc >
OFF 2.16 MPa (313 psi))
Ta ≥ 20°C (68°F):
–1 step/15 sec. (when Pc <
STEP 4 1.77 MPa (257 psi))
OFF OFF
480 pulse (Fully
480 pulse (Fully open)
open)
0 pulse 0 pulse
OFF OFF
OFF OFF
A lapse of 10 sec.
OR
SiUS331708EA
STEP 2
• A lapse of 360 sec.
• Pc – Pe > 0.39 MPa
(56.6 psi)
• Tc > 48°C (118°F)
• Pe < 0.55 MPa (80 psi)
Functions and Control