Panasonic U-72MF2U9 Service Manual page 90

9. Compressor
9. Compressor
9-2-3. Replacing all compressors in a system
(1) Follow the instructions in "2. Discharging Compressor Oil" and drain the oil from the oil separators in all outdoor
units. Measure the amount of drained oil.
(2) Follow the instructions in "9-3. Removing and Installing Compressors" and replace all compressors in the
system.
(3) Follow the instructions in "5. Checking for Leakage After Repair" and check for leaks at all outdoor units and
in the tube.
(4) Follow the instructions in "6. Evacuating System" and apply vacuum to all outdoor units and tube.
(5) Fully close the high- and low-pressure gauge valves on the manifold gauge, then stop the vacuum pump.
(6) Disconnect the manifold gauge from vacuum pump. Connect the manifold gauge to the refrigerant cylinder.
Be especially careful that air does not enter the tube.
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CAUTION
(7) Open the valve on the refrigerant cylinder, and open the high-pressure gauge valve on the manifold gauge.
When charging has been completed with an amount of new refrigerant equal to the amount of recovered
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refrigerant, or when charging with the same amount of new refrigerant has not been completed but no more
refrigerant will enter the unit, first turn the power OFF at the repaired outdoor unit, then remove the short circuit
at the AP pin (CN24). Then fully open all valves on the suction tube, discharge tube, liquid tube, and balance tube.
However, leave the balance tube fully closed if only a single outdoor unit is installed.
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(8) If backup operation was engaged, follow the instructions in "3. Backup Operation" and perform backup operation
recovery.
(9) If charging with an amount of new refrigerant equal to the amount of recovered refrigerant was not possible,
fully close the high-pressure gauge valve on the manifold gauge. Then, while the unit is operating according
to "4-2-1. Cooling operation (for all units)", open the low-pressure gauge valve on the manifold gauge and
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charge with the designated amount of refrigerant.
CAUTION
(10) Fully close the low-pressure gauge valves on the manifold gauge, follow the instructions in "7. Charging
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Compressor Oil", and charge with the necessary amount of oil. Also add an amount of oil that is equivalent to
the amount that was drained from the oil separators.
(11) Remove the manifold gauge.
CAUTION
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(12) Follow the instructions in "9-2-4. Dry core cleaning" and perform dry core cleaning of all outdoor units.
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Do not reuse the recovered refrigerant. Use a refrigerant cylinder that contains unused
refrigerant.
When charging with liquid refrigerant, add refrigerant a little at a time in order to
prevent liquid back-flow.
The connecting port employs a Schrader-type valve. When disconnecting the hose,
pressure will be applied from the refrigerant in the outdoor unit.
Outdoor Unit Repair Procedures
Outdoor Unit Repair Procedures
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2WAY VRF SYSTEM
3WAY VRF SYSTEM