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2WAY VRF SYSTEM
Outdoor Unit Repair Procedures
2WAY VRF SYSTEM
Outdoor Unit Repair Procedures
8. Pumping Out Refrigerant from Outdoor Unit
8-1. If Remote Controller is Used for Maintenance of Outdoor Unit
(1)
(2) Connect the manifold gauge valves at the Lo side to the low-pressure outlet port of the outdoor unit to be
repaired. Also connect the refrigerant recovery cylinder to any one of the normal outdoor units at the liquid tube
service port (Schrader-type push-to-release valve). Perform the connection work quickly so that no air is
allowed to enter. (Fig. 14)
See “3. Backup Operation” and perform backup operation.
(3) Connect the outdoor unit maintenance remote controller to the RC connector (3P) (BLU) (CN73) on the outdoor
unit control PCB of the outdoor unit to be repaired. Then start a test run of all units.
(Press and hold the
(CHECK) button for 4 seconds or longer.)
The hoses may be subject to internal pressure from the refrigerant inside the outdoor
unit. Check that the manifold gauge valves are fully closed beforehand.
A Schrader-type push-to-release valve is provided at each connection port.
* Connecting the refrigerant recovery cylinder is done to prevent pressure from rising excessively during backup
operation by recovering the refrigerant from the outdoor unit to be repaired.
(Measure the weight of the refrigerant and cylinder itself beforehand and provide sufficient safety measures,
such as installing a high-pressure cutout in the circuit.)
CAUTION
Fig. 14
To indoor unit
Measuring scale
Connect from here to
refrigerant recovery unit
Refrigerant
recovery
cylinder
Faulty outdoor unit
Other outdoor unit
Lo
Hi
Manifold
gauge
High-pressure outlet port
(for ø5/16” (ø7.94mm)-
dia connector)
Low-pressure outlet port
(for ø5/16” (ø7.94m)-
dia connector)
Liquid tube service port
(for ø5/16” (ø7.94mm)-
dia connector)
8. Pumping Out Refrigerant from Outdoor Unit
2WAY VRF SYSTEM
Outdoor Unit Repair Procedures
(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, refer to the
“Outdoor unit maintenance remote controller” item.
It is also possible to check the operating conditions either in cooling or heating mode by touching the gas tube.
(5) Close the gas tube and balance tube on the outdoor unit to be repaired. Then slowly close the liquid tube
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 gas tube valve on that outdoor unit.
(7) Connect the high-pressure gauge side of the manifold gauge to the high-pressure outlet port on the outdoor unit
to be repaired, and connect the manifold gauge to the refrigerant recovery device. Be sure that no air enters the
tubing 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.
* 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.
Cooling mode : low temperature (68 °F (20°C) or lower)
Heating mode : high temperature (140 °F (60°C) or higher)
The gas tubing becomes hot (140 °F (60°C) or higher) in heating mode.
Be careful so as not to be burnt when touching the tubing.
CAUTION
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 gas tube valve on the outdoor unit to be
repaired.
CAUTION
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.
CAUTION
8. Pumping Out Refrigerant from Outdoor Unit
NOTE
To determine the completion of refrigerant recovery, follow the instructions that came with the
refrigerant recovery unit.
SM830237-07_北米向け2WAY_VRF.indb 23
18/06/18 18:48:16
