Startup Control; Startup Control In Cooling - Daikin VRV-WIII RWEYQ72PTJU Service Manual

SiUS30-1301

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
Parts Name
Inverter compressor
Inverter cooling fan
Four way valve (Main)
Four way valve (Sub)
Electronic expansion valve (Main)
Electronic expansion valve (Subcooling)
Solenoid valve (Hot gas)
Solenoid valve (Oil return of water heat
exchanger)
Solenoid valve (Receiver gas charging)
Solenoid valve (Receiver gas discharging)
Solenoid valve (Non-operating unit liquid
pipe closing)
Indoor unit fan
Indoor unit electronic expansion valve
Ending condition
Function and Control
Electric
Symbol
Symbol
— M1C
— M1F, M2F
20S1 Y5S
20S2 Y7S
EV1 Y1E
EV3 Y3E
SVP Y1S
SVE Y2S
SVL Y3S
SVG Y4S
SVSL Y6S
— M1F, M2F
EV Y1E
Thermostat ON
Pressure Equalization
Control before Startup
52Hz +2 steps/20 seconds
0 Hz
OFF Inverter cooling fan control
Holding
Holding
0 pulse
0 pulse
OFF
OFF
OFF
OFF
ON
Indoor unit control
0 pulse
1 minute

Startup Control

Startup Control
(until Pc - Pe > 71.05 psi)
OFF
OFF
2000 pulse
0 pulse
ON
OFF
OFF
OFF
ON
Indoor unit control
0 pulse  Initial opening
Max. 5 minutes
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