Oil Return Operation - Panasonic Urban Multi MX1R Series Service Manual

Function
1.7

Oil Return Operation

1.7.1 MX1R Series
In order to collect refrigeration oil held up in connecting piping, the compressor's operating time is counted,
and oil return operation is carried out for 4 minutes every 8 hours (2 hour after turning on the power supply,
and every 8 hours after that).
(When heating, the indoor unit's electric heater is tuned off one minute prior to oil return operation in
preparation for oil return.)
(1) Compressor Operation Frequency
CU-5(5HP)
CU-8(8HP)
*When heating, frequency is lower than that given in the table for the first 30 seconds and 30 seconds after
completion.
*Frequency may drop according to the various types of step-down control. If so, the next oil return must be
carried out 4 hours later.
(2) Opening of the electronic expansion valve
When cooling
When heating
(3) 4-way changeover valve (Y1R)
When cooling: No change
When heating: Switches to cooling mode
(4) Fan and solenoid valve
Step No. changes according to high pressure.
(Step No. becomes higher as high pressure decreases.)
c→d 30 sec. after oil return start or high pressure is less than 16kg/cm
d→e High pressure is less than 8 kg/cm
e→d High pressure is greater than 16.4 kg/cm
d→c High pressure is greater than 22 kg/cm
∗ When heating only
*On when low pressure <0.3 kg/cm
Off when low pressure <0.8 kg/cm
Notes)
1. While the oil return timer is counting, if the compressor frequency continues at 68Hz (38Hz + ON for 8,
2. If on standby (forced thermostat OFF) or the compressor stops due to malfunction during oil return
3. Oil return operation is not carried out for 28 minutes after defrost is completed.
246
Type Cool
106Hz
106Hz+ON
CU-10 106Hz+ON
(10HP)
Outdoor unit
2000 pulses (fully open)
2000 pulses (fully open)
Step No. Y2S
c
ON∗
d
OFF*
e
OFF*
10HP) or more for more than eight minutes with defrosting, the timer is reset and counts again for eight
hours.
operation, the next time the compressor starts, oil return operation is again carried out for four minutes
after completion of soft start.
Heat
96Hz
86Hz+ON
86Hz+ON
Operating indoor unit
2000 pulses (fully open)
2000 pulses (fully open)
Y3S,Y4S
ON
ON
ON
2
(0.78MPa)
2
(1.61MPa)
2
(2.16MPa)
2
(0.029MPa)
2
(0.078MPa)
Function Urban Multi "MX1R, ME1R Series" Using R-407C
PACD011001C2
Indoor unit turned off
1440 pulses
2000 pulses (fully open)
Fan
H(H+ON)
L(H+OFF)
OFF
2
(1.57MPa)