Daikin SkyAir FHQ24PVJU - Oil Return Control

Special Control SiUS281811EA
112 Part 4 Functions and Control
3.2 Oil Return Control
In order to prevent the compressor from running out of oil, oil return control is conducted to recover
oil that has flowed out from the compressor to the system side.
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
Ts1: Suction pipe temperature detected by thermistor R3T
3.2.1 Oil Return Control in Cooling
Starting conditions
 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 operation starts every 8 hours of cumulative operation of the compressor, even if the
reference value is not met.
Outdoor unit
actuator
Electric Symbol
Oil return preparation
control
Oil return control Control after oil return
18/24
class
30/36/42/48
class
Compressor 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
M2F
Fan control (Normal
cooling)
Fan control (Normal
cooling)
Fan control (Normal
cooling)
Main electronic
expansion valve
Y1E Y1E 480 pulse (Fully open) 480 pulse (Fully open) 480 pulse (Fully open)
Subcooling
electronic
expansion valve
— Y3E SH control 0 pulse 0 pulse
Four way valve Y1S Y1S OFF OFF OFF
Hot gas bypass
valve
Y2S — OFF OFF OFF
Ending conditions 20 seconds
x 3 minutes
x
Ts1 – Te < 5qC (9qF)
OR
x 3 minutes
x
Pe < 0.6 MPa (87 psi)
x HTdi > 110°C (230°F)
OR
Indoor unit actuator Cooling oil return control
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