Daikin VRV RXYQ72-384XAYCA, Service Manual

Page: 108 / 419

Special Control SiUS342004EB
101 Part 4 Functions and Control
7.2.1 Oil Return Operation in Cooling

Oil return operation is not conducted before 2 hours have elapsed from the activation of power
supply.

After 2 hours have elapsed, oil return operation starts when the following item meets the
reference value.

Total amount of oil discharged from the compressor
(The total amount of oil discharged from the compressor is computed from Tc, Te, and
compressor loads.)

Oil return control starts every 8 hours of cumulative operation of the compressor, even if the
reference value is not met.
Part name Electric symbol Oil return operation
Compressor M1C Constant low pressure control
Fan motor M1F, M2F For heat exchanger mode
Electronic expansion valve
(Heat exchanger upper)
Y1E
Same as normal control
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 Same as normal control
Solenoid valve (Liquid shutoff) 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 Same as normal control
Ending condition
•
A lapse of 3 min u tes
•
TsA – Te < 3
°
C (5.4°F)
•
A lapse of 12 min u tes while the fre qu ency is
more than that of oil ret u rn operation.
&
OR
Indoor unit actuator Oil return operation
Fan Thermostat ON unit Remote controller setting
Non-operating unit OFF
Thermostat OFF unit Remote controller setting
Electronic expansion valve Thermostat ON unit Normal control
Non-operating unit 224 pulse
Thermostat OFF unit Forced thermostat ON (PI control)
Low-temperature hydrobox unit actuator Oil return operation
Pump Thermostat ON unit Normal control
Non-operating unit Normal control
Thermostat OFF unit Normal control
Electronic expansion valve Thermostat ON unit Normal control
Non-operating unit 0 pulse
Thermostat OFF unit Forced thermostat ON (PI control)