3
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2WAY SYSTEM
Outdoor Unit Repair Procedures
3
4. Recovering Refrigerant
4-2-3. Refrigerant recovery procedures (2): Indoor unit with no ball valve equipped
Refrigerant in all indoor units and the refrigerant tubing circuit can be pumped into the outdoor unit. The maximum
refrigerant storage capacity per a single outdoor unit is approx. 15 k
g
to 20 k
g
. Thus, in order to collect all
refrigerant from the system, a separate refrigerant recovery unit is necessary. Follow these procedures to correctly
perform pump down.
Perform work correctly, according to the work procedures given below.
1 Connect the manifold gauge to the high- and low-pressure outlet ports on the outdoor unit where pump down
will be performed. Be sure that no air enters the tubing at this time.
2 Follow the instructions in “4-2-1. Cooling operation (for all units)” and operate all units in Cooling mode for
approximately 5 minutes. Then fully close the liquid tube valve on the outdoor unit where pump down will be
performed.
3 When the high-pressure gauge reaches 2.8 MPa or higher, or the low-pressure gauge reaches 0.5 MPa or
below, at the outdoor unit where pump down is being performed, press the ON/OFF button on the outdoor
unit maintenance remote controller to stop operation at all units. Then immediately fully close the suction tube
valve on the outdoor unit where pump down is being performed.
* If the outdoor unit maintenance remote controller is unavailable, short-circuit the stop pin (CN28).
It is not necessary to recover the refrigerant from the balance tube. Therefore do
not operate the balance tube valve.
CAUTION
4 Turn off power to all equipment in the system. Then pull out the RC1 connector (4P) (BLU) (CN75) on the out-
door control PCB in the outdoor unit for which pump down has been completed.
* By pulling out the RC1 connector, communication between the main and the sub outdoor units will be isolated.
5 Change the setting of controllable outdoor unit numbers (reduce by 1 unit).
* If the setting is incorrect, the E30 alarm (outdoor unit serial communication signal error) occurs and the unit
will not operate.
6 Turn on power for all equipment in the system and let the remaining outdoor units run in Cooling mode.
7 Repeat steps 1 and 2 and complete pump down for all outdoor units.
8 Using hoses with Schrader-type push-to-release valves, connect the manifold gauge valves to the suction line
service port, the discharge line service port and the liquid line service port in the next outdoor unit to undergo
pump down. (Fig. 5)
Remaining refrigerant in the system may cause internal pressure. Check that each
valve on the manifold gauge is tightly closed. A Schrader-type push-to-release
valve is provided for each connection port.
CAUTION
9 Use hoses to connect the manifold gauge valves, refrigerant recovery unit, and refrigerant recovery cylinder.
Quickly connect each part to prevent air from entering the tubing.
10
Recover remaining refrigerant from the inter-unit tubing and indoor units using the refrigerant recovery unit.
NOTE
To determine the completion of refrigerant recovery, follow the instructions that came with the refrigerant recovery unit.
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