Startup Control; Startup Control In Cooling - Daikin REYQ-XA Service Manual

SiUS371901E

4. Startup Control

This control is used to equalize the pressure in the suction and discharge sides of the compressor prior to 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 or else after the startup, the following control is made and
the position of the four way valve is also determined. Start both the master and the slave units simultaneously to
position the four way valve.
4.1

Startup Control in Cooling

Compressor (M1C)
0 pulse
Electronic expansion
valve (main)
(Y1E)
Step 15
Inverter fan
(M1F + M2F)
DSH: Discharge pipe superheating degree
Pc : High pressure sensor detection value
Pe : Low pressure sensor detection value
Ta : Outdoor air temperature
Refer to page 115 for Step X.
Functions and Control
Frequency step up
5 sec. interval
E
D
C
B
A
0 Hz
3,000 pulse (fully open)
Ta < 20˚C: OFF
(68˚F)
Ta ≥ 20˚C: StepX/2
+3step/15 sec. (Pc > 2.16 MPa (313 psi))
(68˚F) –3step/15 sec. (Pc < 1.77 MPa (257 psi))
Pc – Pe > 0.17 MPa (24.7 psi)
Frequency
(rps)
A
B
C
D
E
Pc – Pe > 0.42 MPa (60.9 psi)
Pc – Pe > 0.32 MPa (46.4 psi)
&
OR
20 rps or more
DSH > 10˚C (18˚F)
Startup Control
REYQ72-120XA REYQ144/168XA
19 16.4
24 16.4
29 18
38 24
57 36
108