Panasonic U-72MF2U9 Service Manual page 84

8. Pumping Out Refrigerant from Outdoor Unit
8. Pumping Out Refrigerant from Outdoor Unit
(4) Use the outdoor unit maintenance remote controller to check the operating status of the indoor units.
Check that all units are operating in Heating mode.
For details concerning operation of the outdoor unit maintenance remote controller, see the section "Outdoor
unit maintenance remote controller".
It is also possible to check the operating conditions either in cooling or heating mode by touching the suction
tube, discharge tube.
Cooling mode : low temperature (68 °F (20°C) or lower)
Heating mode : high temperature (140 °F (60°C) or higher)
CAUTION
(5) Close the suction tube and balance tube on the outdoor unit to be repaired. Then slowly close the liquid tube
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service valve.
(6) When the low pressure at the outdoor unit to be repaired reaches 72.5 psi (0.5MPa) or below, press the
(ON/OFF) button on the outdoor unit maintenance remote controller to stop all the units.
Then immediately fully close the discharge tube valve on that outdoor unit.
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CAUTION
(7) Connect the high-pressure gauge side of the manifold gauge to the high-pressure outlet port on the outdoor unit
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to be repaired, and connect the manifold gauge to the refrigerant recovery device. Be sure that no air enters the
tube at this time.
(8) Short-circuit the AP pin (CN24) on the outdoor unit control PCB of the unit to be repaired. Then turn ON the
outdoor unit power.
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CAUTION
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* Open both Hi- and Lo-side valves on the manifold gauge valves, and recover the refrigerant remaining in
the outdoor unit. After that, measure the amount of recovered refrigerant.
NOTE
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The discharge tube becomes hot (140 °F (60°C) or higher) in heating mode.
Be careful so as not to be burnt when touching the tube.
While closing the valves, the rise in discharge temperature or another factor may
cause a protective device to activate, stopping the operation of the outdoor unit.
If this occurs, immediately fully close the discharge tube valve on the outdoor unit to be
repaired.
When the AP pin (CN24) is short-circuited and the power is turned ON, all solenoid
valves in the outdoor unit are forced open, allowing the refrigerant to be recovered
from all tubes which are separated by solenoid valves. If this work is not performed,
it will not be possible to recover all of the refrigerant at the refrigerant recovery
device. Be sure to perform this step.
To determine the completion of refrigerant recovery, follow the instructions that came with the
refrigerant recovery unit.
Outdoor Unit Repair Procedures
Outdoor Unit Repair Procedures
2 - 20
2WAY VRF SYSTEM
3WAY VRF SYSTEM