SiUS342004EB
Special Control
Part 4 Functions and Control
102
7.3 Defrost Operation
To defrost the outdoor heat exchanger while in Evaporator, the defrost operation is conducted to
recover the heating capacity.
Tb: Heat exchanger deicer temperature
Part name
Electric symbol
Defrost operation
Compressor
M1C
RXYQ72-120XA, RXYQ72-120XB: 134 rps
RXYQ144/168XA, RXYQ144/168XB: 119 rps
Fan motor
M1F, M2F
With high pressure
OFF
Step X/2
Step X
Electronic expansion valve
(Heat exchanger upper)
Y1E
100%
Electronic expansion valve
(Heat exchanger lower)
Y3E
Electronic expansion valve
(Subcooling heat exchanger)
Y2E
0 pulse
Electric expansion valve
(Subcooling injection)
Y4E
760 pulse
Electronic expansion valve
(Refrigerant cooling)
Y5E
Same as normal control
Electronic expansion valve
(Receiver gas purge)
Y7E
0 pulse
Solenoid valve (Oil separator oil return)
Y1S
ON
Solenoid valve (Hot gas bypass)
Y2S
OFF
Solenoid valve (Liquid pipe)
Y3S
ON
Four way valve (HP/LP gas pipe)
Y4S
Hold
Four way valve (Heat exchanger lower)
Y5S
Hold
Four way valve (Heat exchanger upper)
Y6S
Hold
Solenoid valve (Accumulator oil return)
Y7S
ON
Ending condition
•
A lapse of 15 min
u
tes
•
T
b
>11°C (51.8°F) contin
u
es for 30 seconds or more
OR
Indoor unit actuator
Defrost operation
Fan
Thermostat ON unit
OFF
Non-operating unit
OFF
Thermostat OFF unit
OFF
Electronic expansion valve
Thermostat ON unit
Defrost EV opening degree
Non-operating unit
Defrost EV opening degree
Thermostat OFF unit
Defrost EV opening degree
Low-temperature hydrobox unit actuator
Defrost operation
Pump
Thermostat ON unit
Normal control
Non-operating unit
Normal control
Thermostat OFF unit
Normal control
Electronic expansion valve
Thermostat ON unit
0 pulse
Non-operating unit
0 pulse
Thermostat OFF unit
0 pulse
Summary of Contents for VRV RXYQ72-384XAYCA
Page 1: ...Service Manual RXYQ72 384XAYCA RXYQ72 384XBYCA Heat Pump 60 Hz SiUS342004EB...
Page 395: ...SiUS342004EB Wiring Diagrams Part 7 Appendix 388 FXFQ07 09 12 15 18 24 30 36 48TVJU 3D086460B...
Page 397: ...SiUS342004EB Wiring Diagrams Part 7 Appendix 390 FXZQ05 07 09 12 15 18TAVJU 3D110443A...
Page 401: ...SiUS342004EB Wiring Diagrams Part 7 Appendix 394 FXEQ07 09 12 15 18 24PVJU 3D098557A...
Page 402: ...Wiring Diagrams SiUS342004EB 395 Part 7 Appendix FXDQ07 09 12 18 24MVJU C 3D050501C...
Page 409: ...SiUS342004EB Wiring Diagrams Part 7 Appendix 402 FXHQ12 24 36MVJU 3D048116C...
Page 410: ...Wiring Diagrams SiUS342004EB 403 Part 7 Appendix FXAQ07 09 12 18 24PVJU 3D075354F...
Page 418: ...Wiring Diagrams SiUS342004EB 411 Part 7 Appendix VAM1200GVJU 3D073270D...