Startup Control; Startup Control In Cooling; Startup Control In Heating - Daikin VRV EMERION RXYQ-AATJA Service Manual

SiUS342303E

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 liquid refrigerant 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 sub units simultaneously to position the four way valve.
DSH: Discharge pipe superheating degree
Pc: High pressure sensor detection value
Pe: Low pressure sensor detection value
Ta: Outdoor air temperature
4.1

Startup Control in Cooling

4.2

Startup Control in Heating

Frequency
RXYQ72AA
(rps)
A 15
B 23
C 28
D 37.3
E 51.4
F 6.2
Part 4 Functions and Control
0 rps
Compressor motor
(M1C) (M2C)
0 pulse
Electronic expansion
valve (Y1E) (Y6E)
Step 4
Fan motor
(M1F + M2F)
Pc – Pe > 0.17 MPa (24.7 psi)
0 rps
Compressor motor
(M1C) (M2C)
0 pulse
Electronic expansion
valve (Y1E) (Y6E)
Step 1
Fan motor
(M1F + M2F)
Pc – Pe > 0.17 MPa (24.7 psi)
RXYQ96/120AA
M1C
26
37
45
60
82
5
Rotation speed step up
5 sec. interval
E
D
C
B
A
3,000 pulse (fully open)
Ta < 20°C: OFF
(68°F)
+1 step/15 sec. (Pc > 2.16 MPa (313 psi)
Ta ≥ 20°C: Step 4
–1 step/15 sec. (Pc < 1.77 MPa) (257 psi)
(68°F)
Rotation speed step up
5 sec. interval
E
D
+F/10 sec.
C
B
A A
Initial
PI control
opening
Maximum step
RXYQ144/168AA
M2C M1C
26 26
37 37
45 45
60 60
82 82
5 3.8

Startup Control

EV indoor opening
OR
Tcmax > 48°C (118.4°F)
Pcmax > 2.45 MPa (355 psi)
RXYQ192/216/240AA
M2C M1C
15 15
23 23
28 28
37.3 37.3
51.4 51.4
3.8 6.8
M2C
15
23
28
37.3
51.4
6.8
102