Special Control
SiUS341802E
63
Functions and Control
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
Inverter compressor
M1C
RXLQ72TA, RXYQ72-120TA: 134 rps
RXLQ96/120TA, RXYQ144/168TA: 119 rps
Inverter fan
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 operation
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 minutes
•
Tb>11°C (51.8°F) continues for 30 seconds or more
OR
Indoor unit actuator
Defrost operation
Fan
Thermostat ON unit
OFF
Stopping unit
OFF
Thermostat OFF unit
OFF
Electronic expansion
valve
Thermostat ON unit
Defrost EV opening degree
Stopping unit
Defrost EV opening degree
Thermostat OFF unit
Defrost EV opening degree
Summary of Contents for Aurora Series
Page 317: ...SiUS341802E Wiring Diagrams Appendix 304 RXLQ96 120TATJU 2D112581A ...
Page 318: ...Wiring Diagrams SiUS341802E 305 Appendix RXLQ72TAYDU 2D112582A ...
Page 319: ...SiUS341802E Wiring Diagrams Appendix 306 RXLQ96 120TAYDU 2D112583A ...
Page 331: ...SiUS341802E Wiring Diagrams Appendix 318 VAM1200GVJU 3D073270C ...
Page 332: ...Revision History Month Year Version Revised contents 04 2018 SiUS341802E First edition ...