Defrost Operation - Daikin RXYQ96PYDN Service Manual

SiUS34-801A_b
Cooling indoor unit actuator
Fan
Motorized valve
Heating indoor unit actuator
Fan
Motorized valve
Cooling BS unit actuator
Electronic expansion valve (EVH)
Electronic expansion valve (EVL)
Electronic expansion valve (EVHS)
Electronic expansion valve (EVLS)
Electronic expansion valve (EVSC)
Heating BS unit actuator
Electronic expansion valve (EVH)
Electronic expansion valve (EVL)
Electronic expansion valve (EVHS)
Electronic expansion valve (EVLS)
Electronic expansion valve (EVSC)
7.4

Defrost Operation

[Start conditions]
Referring to the following conditions, start defrost operation.
• When there is a decrease in the coefficient of heat transfer of outdoor unit heat exchanger
• When there is a drop in the temperature of outdoor unit heat exchanger outlet (Tb)
&
• When the low pressure stays low for a certain amount of time (2 hours minimum)
Furthermore, the thermal conductivity of outdoor unit heat exchanger is calculated by Tc, Te, and compressor loads.
Defrosting outdoor unit actuator
Compressor 1
Compressor 2
Outdoor unit fan 1
Outdoor unit fan 2
Four-way valve (for heat changer
selection)
Four-way valve (for high- and low-
pressure gas pipe selection)
Electronic expansion valve (main) EVM
VRVIII R-410A Heat Recovery 60Hz
Thermo ON unit
Unit not in operation
Thermo OFF unit
Thermo ON unit
Unit not in operation
Thermo OFF unit
Thermo ON unit
Unit not in operation
Thermo OFF unit
Thermo ON unit
Unit not in operation
Thermo OFF unit
Elect. symbol
Y4E
Y5E
Y2E
Y3E
Y1E
Elect. symbol
Y4E
Y5E
Y2E
Y3E
Y1E
Elect.
symbol
Symbol
REYQ REMQ
M1C M1C REYQ72·96·120·144P: 232Hz+ON
— REMQ72P: 210Hz
REMQ96·120P: 210Hz+ON
M2C M2C
M1F M1F
Pcmax>355.25psi
—
Pcmax>440.8psi
M2F M2F
Y2S
20SA Y3S OFF
Y9S
20SB Y8S Y2S Holds
Y1E
Y1E 1375pls
Y3E
Oil return operation
Remote controller setting
Remote controller setting
Normal opening degree
Normal opening degree for forced thermostat ON
Oil return operation
Remote controller setting
Normal opening degree
Normal opening degree for forced thermostat ON
Oil return operation
0pls (60pls when Pc_max>413.25psi)
Oil return operation
0pls (60pls when Pc_max>413.25psi)
0pls (PI control at simultaneous cooling / heating
Defrost operation
OFF
Pcmax<342.2psi
FANSTEP4
Pcmax<427.75psi
FANSTEP6
Special Control
OFF
192pls
OFF
LL
224 pls
0pls
760pls
480pls
PI control
760pls
0pls
60pls
operation)
Operation after defrost
REYQ72·96·120·144P: upper limit
124Hz(STD Holds)
REMQ72P: 210Hz
REMQ96·120P: 210Hz+ON
OFF
Pcmax>355.25psi
Pcmax<342.2psi
FANSTEP4
Pcmax>440.8psi Pcmax<427.75psi
FANSTEP6
OFF
Holds
0pls
203