Oil Return Control - Daikin REYQ-XA Service Manual

SiUS371901E
7.2

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.
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 Control in Cooling Operation
Starting conditions
Referring to the set conditions for the following items, start the oil return control in cooling
• Cumulative oil feed rate
• Timer setting (Make this setting so as to start the oil return control 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
Compressor
Inverter fan
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
Functions and Control
Electric symbol
M1C Constant low pressure control
M1F, M2F For heat exchanger mode
Y1E
Same as normal control
Y3E
Y2E 0 pulse
Y4E 760 pulse
Y5E Same as normal control
Y7E 0 pulse
Y1S ON
Y2S Same as normal control
Y3S ON
Y4S Hold
Y5S Hold
Y6S Hold
Y7S Same as normal control
• A lapse of 3 minutes
&
OR
Oil return control
• TsA – Te < 3°C (5.4°F)
• A lapse of 12 minutes while the frequency is
more than that of oil return control.
Special Control
124