SiUS30-1301
Startup Control
Function and Control
47
4. Startup Control
This startup control provides the following control to reduce the compressor load resulting from
liquid return or else during compressor startup, and also determine the position of four way valves.
4.1
Startup Control in Cooling
Both master and slave units operate same time for changing four way valve position
Normal
operation after completion.
Pc: Value detected by high pressure sensor
Pe: Value detected by low pressure sensor
Thermostat ON
Parts Name
Symbol
Electric
Symbol
Pressure Equalization
Control before Startup
Startup Control
Inverter compressor
—
M1C
0 Hz
52Hz +2 steps/20 seconds
(until Pc - Pe > 71.05 psi)
Inverter cooling fan
—
M1F, M2F
OFF
Inverter cooling fan control
Four way valve (Main)
20S1
Y5S
Holding
OFF
Four way valve (Sub)
20S2
Y7S
Holding
OFF
Electronic expansion valve (Main)
EV1
Y1E
0 pulse
2000 pulse
Electronic expansion valve (Subcooling)
EV3
Y3E
0 pulse
0 pulse
Solenoid valve (Hot gas)
SVP
Y1S
OFF
ON
Solenoid valve (Oil return of water heat
exchanger)
SVE
Y2S
OFF
OFF
Solenoid valve (Receiver gas charging)
SVL
Y3S
OFF
OFF
Solenoid valve (Receiver gas discharging)
SVG
Y4S
OFF
OFF
Solenoid valve (Non-operating unit liquid
pipe closing)
SVSL
Y6S
ON
ON
Indoor unit fan
—
M1F, M2F
Indoor unit control
Indoor unit control
Indoor unit electronic expansion valve
EV
Y1E
0 pulse
0 pulse
Initial opening
Ending condition
1 minute
Max. 5 minutes