SiAF332111E Control for 4/5/10/12 HP Outdoor Unit
Part 4 Functions and Control 61
1.3.2 Oil Return Control
In order to prevent the compressor from running out of oil, the oil return control is conducted to
recover oil that has flowed out from the compressor to the system side.
Oil Return Control in Cooling Operation
HTdi: Compressor discharge pipe temperature (Tdi) compensated with outdoor air temperature
Pe: Low pressure sensor detection value
Tc: High pressure equivalent saturation temperature
Te: Low pressure equivalent saturation temperature
Ts: Suction pipe temperature detected by thermistor
Starting
Conditions
Oil return control is not conducted before 2 hours have elapsed from the activation of power
supply.
After 2 hours have elapsed, oil return control 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.
Oil Return Control
Outdoor unit
actuator
Electric symbol
Oil return
preparation
control
Oil return control
Control after
oil return
RXQ4ARV1 RXQ5ARV1
RXMQ
10/12ARY1
Compressor
M1C M1C M1C
Take the current
step as the
upper limit.
Minimum frequency
( Low pressure
protection control)
Same as oil return
control.
Outdoor fan
M1F M1F
M1F
M2F
Fan control
(Normal cooling)
Fan control
(Normal cooling)
Fan control
(Normal cooling)
Electronic
expansion
valve (Main)
―—Y1E
Fully open Fully open Fully open
Electronic
expansion
valve
(Injection)
―—Y2E
SH control 0 pulse 0 pulse
Hot gas
bypass valve
Y2S — ―
OFF OFF OFF
Ending conditions 20 seconds
• 3 minutes
• Ts – Te < 5°C
OR
• 3 minutes
• Pe < 0.6 MPa
• HTdi > 110°C
OR
Indoor unit actuator Cooling oil return control
Indoor fan
Thermostat ON unit Remote controller setting
Non-operating unit OFF
Thermostat OFF unit Remote controller setting
Electronic expansion valve
Thermostat ON unit Normal opening
Non-operating unit 224 pulse
Thermostat OFF unit Normal opening with forced thermostat ON
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