Oil Return Operation - Daikin REYQ-TA 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 conditions
Referring to the set conditions for the following items, start the oil return operation in cooling
• Cumulative oil feed rate
• Timer setting (Make this setting so as to start the oil return operation when the initial cumulative operating time reaches 2
hours after power supply is turned ON and then every 8 hours.)
Furthermore, the cumulative oil feed rate is computed from Tc, Te, and compressor loads.
Part Name
Inverter compressor 1
Inverter compressor 2
Inverter fan
Electronic expansion valve (Heat
exchanger upper)
Electronic expansion valve (Heat
exchanger lower)
Electronic expansion valve
(Subcooling heat exchanger)
Electronic expansion valve
(Receiver gas purge)
Electronic expansion valve (Inverter cooling) Y5E
Solenoid valve (Oil separator oil return)
Solenoid valve (Liquid pipe)
Four way valve (HP/LP gas pipe)
Four way valve (Heat exchanger lower)
Four way valve (Heat exchanger upper) Y6S
Ending condition
Fan
Electronic expansion valve
Branch selector unit actuator
Electronic
expansion valve Y1E
(EVSC)
Electronic
expansion valve Y2E
(EVH)
Electronic
expansion valve Y3E
(EVL)
81
Electric Symbol
REYQ72TA
M1C M1C
— M2C
M1F M1F, M2F
Y1E Y1E
Y3E Y3E
Y2E Y2E
Y4E Y4E
Y5E
Y1S Y1S, Y2S
Y3S Y3S
Y4S Y4S
Y5S Y5S
Y6S
Indoor unit actuator
Thermostat ON unit
Stopping unit
Thermostat OFF unit
Thermostat ON unit
Stopping unit
Thermostat OFF unit
Thermostat ON
Stopping
Thermostat OFF
Thermostat ON
Stopping
Thermostat OFF
Thermostat ON
Stopping
Thermostat OFF
REYQ96-168TA
Constant low pressure control
For heat exchanger mode
Same as normal operation
0 pulse
0 pulse
Same as normal operation
ON
ON
Hold
Hold
Hold
• A lapse of 3 minutes
&
OR
Normal cooling
Cooling
0 pulse
0 pulse
0 pulse
6,000 pulse
6,000 pulse
6,000 pulse
6,000 pulse
6,000 pulse
6,000 pulse
SiUS371614E

Oil return operation

• TsA – Te < 3°C (5.4°F)
• A lapse of 12 minutes while the
frequency is more than that of oil
return operation.
Oil return operation
Remote controller setting
OFF
Remote controller setting
Normal control
224 pulse
Forced thermostat ON (PI control)
Functions and Control