Daikin VRV S RXQ4/5ARV1 - Special Control

SiAF332111E Control for 6/8 HP Outdoor Unit
Part 4 Functions and Control 79
2.7 Special Control
2.7.1 Pump Down Residual Control
Pc : High pressure sensor detection value
Pe : Low pressure sensor detection value
To avoid refrigerant emigration when outdoor unit stops operation (thermostat or safety), all
electronic expansion valves are closed.
2.7.2 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
Ts1: Suction pipe temperature detected by thermistor R3T
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 in Cooling Operation
Part Name
Electric
Symbol
RXMQ-AR Function
Compressor motor M1C  Capacity step PI control
Fan motor M1F  TC control
Electronic expansion valve (Injection) Y2E  0 pulse
Electronic expansion valve
(Refrigerant auto charge)
Y4E 
480 pulse
Ending conditions
&
OR
· A lapse of 3 minutes.
· Ts1–Te < 3°C
·
A lapse of 6 minutes
while the frequency
is more than that of
oil return control.
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 control
Non-operating unit 224 pulse
Thermostat OFF unit Normal control with forced thermostat
ON