Panasonic U-72MF2U9 Service Manual page 88

9. Compressor
9. Compressor
9-2. Replacing the Compressor(s)
9-2-1. Replacing only the failed compressor
(1) If backup operation is required, follow the instructions in "3. Backup Operation" and engage backup operation.
(2) Follow the instructions in "9-3. Removing and Installing Compressors" and replace the failed compressor.
(3) Fully close the high- and low-pressure gauge valves on the manifold gauge, then stop the vacuum pump.
(4) Disconnect the manifold gauge from vacuum pump.
Connect the manifold gauge to the cylinder where the refrigerant was recovered.
At this time, be careful that air does not enter the tube.
(5) Open the valve on the refrigerant recovery cylinder and the high-pressure gauge valve on the manifold gauge
to charge with refrigerant.
At this time, the low-pressure gauge valve on the manifold gauge remains fully closed.
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CAUTION
(6) When charging has been completed with an amount of new refrigerant equal to the amount of recovered
refrigerant, or when charging with the same amount of new refrigerant has not been completed but no more
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refrigerant will enter the unit, fully close the high-pressure gauge valve on the manifold gauge.
Next, turn the power OFF at the repaired outdoor unit, then remove the short circuit at the AP pin (CN24).
Finally, 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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(7) If backup operation was engaged, follow the instructions in "3. Backup Operation" and perform backup operation
recovery.
(8) 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 in "4-2-1.
Cooling operation (for all units)", open the low-pressure gauge valve on the manifold gauge and charge with
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the designated amount of refrigerant.
CAUTION
(9) 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 oil if necessary.
(10) Remove the manifold gauge.
CAUTION
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If the recovered refrigerant becomes mixed with another refrigerant or another gas
(such as nitrogen or air), do not use the recovered refrigerant for charging. Charge
with the designated amount of new 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 push-to-release valve. When disconnecting
the hose, pressure will be applied from the refrigerant in the outdoor unit.
Outdoor Unit Repair Procedures
Outdoor Unit Repair Procedures
2 - 24
2WAY VRF SYSTEM
3WAY VRF SYSTEM