Oil Return Operation - Panasonic Urban Multi MX1R Series Service Manual

PACD011001C2
1.7

Oil Return Operation

1.7.1 MX1 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
‹ When heating, frequency is lower than that given in the table for the first 30 seconds and 30 seconds
‹ Frequency may drop according to the various types of step-down control. If so, the next oil return must
2. Opening of the Electronic Expansion Valve
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.)
Step 1 → Step 2 30 sec. after oil return start or high pressure < 16kg/cm² (1.57MPa)
Step 2 → Step 3 High pressure < 7.5 kg/cm² (0.74MPa)
Step 3 → Step 2 High pressure > 15 kg/cm² (1.47MPa)
Step 2 → Step 1 High pressure > 20 kg/cm² (1.96MPa)
∗ When heating only
∗∗ On when low pressure < 0.3 kg/cm² (0.029MPa)
Off when low pressure > 0.8 kg/cm² (0.078MPa)
1. If the compressor frequency continues at 68Hz (38Hz+ON for 8, 10HP) or more for more than eight
Notes:
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 defrosting is completed.
Function Urban Multi "MX1, ME1 Series" Using R-22
Type
CU-5 (5HP)
CU-8 (8HP)
CU-10 (10HP)
after completion.
be carried out 4 hours later.
Outdoor unit
When cooling 2000 pulses (fully open)
When heating 2000 pulses (fully open)
Step No.
1
2
3
minutes with defrosting while the oil return timer is counting, 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.
Cool
106Hz
106Hz+ON
106Hz+ON
Operating indoor unit
2000 pulses (fully open)
2000 pulses (fully open)
Y2S Y3S, Y4S
ON∗
OFF∗∗
OFF∗∗
Heat
96Hz
86Hz+ON
86Hz+ON
Indoor unit turned off
1440 pulses
2000 pulses (fully open)
Fan
ON H(H+ON)
ON L(H+OFF)
ON OFF
Function
31