Defrost Operation - Daikin Aurora Series Service Manual

Special 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
Inverter compressor
Inverter fan
Electronic expansion valve (Heat
exchanger upper)
Electronic expansion valve (Heat
exchanger lower)
Electronic expansion valve (Subcooling
heat exchanger)
Electric expansion valve (Subcooling
injection)
Electronic expansion valve (Refrigerant
cooling)
Electronic expansion valve (Receiver
gas purge)
Solenoid valve (Oil separator oil return) Y1S
Solenoid valve (Hot gas bypass)
Solenoid valve (Liquid pipe)
Four way valve (HP/LP gas pipe)
Four way valve (Heat exchanger lower) Y5S
Four way valve (Heat exchanger upper) Y6S
Solenoid valve (Accumulator oil return) Y7S
Ending condition
Indoor unit actuator
Fan
Electronic expansion
valve
63
Electric Symbol
M1C
M1F, M2F
Y1E
Y3E
Y2E
Y4E
Y5E
Y7E
Y2S
Y3S
Y4S
Thermostat ON unit OFF
Stopping unit OFF
Thermostat OFF unit OFF
Thermostat ON unit Defrost EV opening degree
Stopping unit Defrost EV opening degree
Thermostat OFF unit Defrost EV opening degree

Defrost operation

RXLQ72TA, RXYQ72-120TA: 134 rps
RXLQ96/120TA, RXYQ144/168TA: 119 rps
With high pressure
←→ ←→
OFF Step X/2
100%
0 pulse
760 pulse
Same as normal operation
0 pulse
ON
OFF
ON
Hold
Hold
Hold
ON
• A lapse of 15 minutes
OR
• Tb>11°C (51.8°F) continues for 30 seconds or more
Defrost operation
SiUS341802E
Step X
Functions and Control