Startup Control; Cooling Startup Control; Heating Startup Control - Daikin VRV RXYMQ-A Series Service Manual

SiME332106E

4. Startup Control

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.
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.
Pc : High pressure sensor detection value
Pe : Low pressure sensor detection value
Ta : Outdoor air temperature
Te : Low pressure equivalent saturation temperature
Td : Discharge temperature
4.1

Cooling Startup Control

4.2

Heating Startup Control

Compressor (M1C)
Electronic expansion
valve (main) (Y1E)
Fan motor (M1F)
Part 4 Functions and Control
0 Hz
Compressor (M1C)
0 pulse
Electronic expansion
valve (Main)
(Y1E)
0 pulse
Electronic expansion
valve (Refrigerant jacket)
(Y3E)
0 pulse
Electronic expansion
valve (Injection)
(Y2E)
Step4
Inverter fan (M1F)
+15 Hz/20 sec.
Min.
step
15 sec.
0 Hz
'T (Ta – Te) control
0 pulse
Step 7Y
Step 4
15 min. elapsed
Four way valve ON
OR &
Td – Te > 10°C
Frequency step up
5 sec. interval
480 pulse (fully open)
480 pulse (fully open)
Ta < 20°C: OFF +1step/15 sec. (Pc > 2.16 MPa)
Ta t 20°C: Step4
–1step/15 sec. (Pc < 1.77 MPa)
INV d 20 rps
&
Pc – Pe t 0.42 MPa
OR
INV > 20 rps
&
Pc – Pe t 0.32 MPa
45 sec. elapsed
10 sec. elapsed
OR &
Inverter frequency matched
Startup Control
Te < 10°C
&
Te < Th2( ) – 10
Th2 in "Pre-pressure
equalization"
Normal control
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