Daikin VRV IV-S RXTQ-TAVJU Series Service Manual page 53

SiUS331604E
3.2.2 Oil Return Operation in Heating
Pc : High pressure sensor detection value
Pe : Low pressure sensor detection value
Tc : High pressure equivalent saturation temperature
Te : Low pressure equivalent saturation temperature
Ts1 : Suction pipe temperature detected by suction 1 thermistor
Tb : Heat exchanger temperature
Starting conditions
Referring to the set conditions for the following items, start oil return operation in heating.
• Integrated amount of displaced oil
• Timer setting (After the power is turned ON, integrated operating time is two hours and subsequently every
eight hours.)
In addition, integrated amount of displaced oil is derived from Tc, Te, and compressor load.
Electric symbol
Outdoor unit
RXTQ36
actuator
TAVJU
Compressor M1C M1C M1C Upper limit control
Outdoor fan M1F
Four way valve Y1S
Main electronic
Y1E
expansion valve
Subcooling

electronic
expansion valve
Hot gas bypass
Y2S
valve
Ending conditions
∗ From the preparing oil-returning operation to the oil-returning operation, and from the oil-returning operation
to the operation after oil-returning, the compressor stops for 1 minute to reduce noise on changing of the four
way valve.
Indoor fan
Electronic expansion valve
Functions and Control
Oil return preparation
RXTQ48 RXTQ60
operation
TAVJU TAVJU
M1F,
M1F M2F STEP 8
Y1S Y1S ON
Y1E Y1E SH control

Y3E 0 pulse
 
OFF
2 minutes
Indoor unit actuator
Thermostat ON unit
Stopping unit
Thermostat OFF unit
Thermostat ON unit
Stopping unit
Thermostat OFF unit
Oil return operation
140 Hz Full load
OFF
OFF
480 pulse (Fully open)
0 pulse
OFF
• 12 minutes
OR
• Ts1 – Te < 5°C (9°F)
&
• Tb > 11°C (51.8°F)
Heating oil return operation
416 pulse
256 pulse
416 pulse
Special Control
After oil return operation
Increases 2 steps every 20
seconds from minimum
frequency until Pc – Pe >
0.4 MPa (58 psi) is achieved.
STEP 8
ON
55 pulse
0 pulse
OFF
• 160 seconds
OR
• Pc – Pe > 0.4 MPa
(58 psi)
OFF
OFF
OFF
40