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4. Backup Operation
<If the failed unit is the No. 1 outdoor unit (main unit)>
If the No. 1 unit (main unit) has failed, a different outdoor unit must be set as the No. 1 unit (main unit).
• Settings at the failed No. 1 outdoor unit
– No particular changes
– However, close all service valves (suction tube, discharge tube, liquid tube, balance tube) at the failed outdoor
unit, and disconnect the wiring between the outdoor units (main-sub unit wiring).
• Settings at No. 1 unit (main unit)
Switch on outdoor unit control PCB
System address (S003, S002)
No. of indoor units (S005, S004)
No. of outdoor units (S006)
Outdoor unit No. (S007)
To this outdoor unit, connect the inter-unit communication line which was previously connected to the
No. 1 unit (main unit).
CAUTION
• Settings at other outdoor units
No particular changes.
(2) Adjusting the refrigerant for backup operation
During backup operation, all of the service valves on the failed unit are closed. However, if a check of the
backup operating conditions shows that the level of gas is low, recover the refrigerant from the failed outdoor
unit. If the level of gas is too high, collect refrigerant at the failed outdoor unit.
● Recovering refrigerant
With the normal outdoor units operating, monitor the operating condition and open/close the suction tube
service valve on the failed outdoor unit where all the service valves were closed. In this way, recover
refrigerant from the failed outdoor unit in order to adjust the amount of refrigerant in the system.
After adjusting the amount of refrigerant, close the suction tube valve at the failed outdoor unit.
● Collecting refrigerant in the failed outdoor unit
• Short-circuit the vacuum application pin (CN102) on the control PCB of the failed outdoor unit where the
service valves are closed, then turn the power ON. Also disconnect the wiring between the outdoor units.
• With the normal outdoor units operating, monitor the operating condition and open/close the liquid tube
service valve on the failed outdoor unit where all the service valves were closed. In this way, collect
refrigerant in the failed outdoor unit in order to adjust the amount of refrigerant in the system.
Make the same settings as on the failed No. 1 unit.
Make the same settings as on the failed No. 1 unit.
Subtract the number of failed units from the current setting.
Change to "1."
After recovery work is completed, return the outdoor unit No. setting (now =
1) to the value it was before the failure and repair. If this is not done, there will
be duplicated outdoor unit No. settings. In this case an alarm does not occur
immediately, however operation may be unstable.
Reconnect the inter-unit communications line to the No. 1 unit.
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3-WAY ECO-i SYSTEM
Outdoor Unit Repair Procedures
Action
2
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