Oil Return Operation - Daikin VRV Aurora RXLQ-TATJU Series Service Manual

Special Control
7.2

Oil Return Operation

In order to prevent the compressor from running out of oil, the oil return operation is conducted to
recover oil that has flowed out from the compressor to the system side.
Tc : High pressure equivalent saturation temperature
Te : Low pressure equivalent saturation temperature
TsA: Suction pipe temperature detected by thermistor R3T
7.2.1 Oil Return Operation in Cooling Operation
Starting
 Oil return operation is not conducted before 2 hours have elapsed from the activation of power
Conditions
 After 2 hours have elapsed, oil return operation starts when the following item meets the
 Oil return control starts every 8 hours of cumulative operation of the compressor, even if the
Part name
Compressor
Fan motor
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)
Solenoid valve (Hot gas bypass)
Solenoid valve (Liquid shutoff)
Four way valve (HP/LP gas pipe)
Four way valve (Heat exchanger lower)
Four way valve (Heat exchanger upper)
Solenoid valve (Accumulator oil return)
Ending condition
Fan
Electronic expansion valve
105
supply.
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.)
reference value is not met.
Electric symbol
M1C
M1F, M2F
Y1E
Y3E
Y2E
Y4E
Y5E
Y7E
Y1S
Y2S
Y3S
Y4S
Y5S
Y6S
Y7S
Indoor unit actuator
Thermostat OFF unit
Thermostat OFF unit
Constant low pressure control
For heat exchanger mode
Same as normal control
0 pulse
760 pulse
Same as normal control
0 pulse
ON
Same as normal control
ON
Hold
Hold
Hold
Same as normal control
• A lapse of 3 minutes
• TsA – Te < 3°C (5.4°F)
&
• A lapse of 12 minutes while the frequency is
OR
more than that of oil return operation.
Thermostat ON unit
Non-operating unit
Thermostat ON unit
Non-operating unit
SiUS341802EC
Oil return operation
Oil return operation
Remote controller setting
OFF
Remote controller setting
Normal control
224 pulse
Forced thermostat ON (PI control)
Part 4 Functions and Control