Processes and Functions
6
TD831077
VI - 10
¶ Types of backup operation
(1) Electrically disconnecting a unit
1 Disconnect the inter-control unit wire from the faulty outdoor unit, and set the number of C.C.U. AD units to the
number of outdoor units that are connected electrically minus one.
2 Close the service valve of the faulty unit.
3 In this state, perform operation to check the operating status.
¶ This completes the procedure.
¶ If the PC unit is faulty, leave the power on for the C.C.U. If the PC unit is electrically disconnected, opera-
tion is not performed unless a request with a capacity of one or more AD units is received from the indoor
unit.
4 Settings for allowing backup operation
¶ Change the settings of the C.C.U. DIP switch S6.
Example : When three outdoor units are installed
Example 1: When there is one PC unit and one AD unit (one AD unit is faulty)
←
Set to the number of outdoor units that are connected minus one. In this example 2-1=1.
Example 2: When there are two AD units (PC unit is faulty)
←
Set to the number of outdoor units that are connected minus one. In this example 2-1=1.
(2) Backup operation when a compressor in the PC unit is faulty
¶ Backup operation using only the PC unit is still possible when one of the PC unit compressors is faulty.
1 Setting the backup switch and CT switch combinations on the outdoor unit control P.C.B. allows operation
while ignoring the protection control mechanisms of the faulty compressor.
1) Backup operation is an emergency measure in the event of a fault.
2) The settings on the C.C.U. do not need to be changed.
2 Settings for allowing backup operation
Change the settings of the PC unit outdoor unit control P.C.B. DIP switch S1.
Example 1 : When the AC compressor is faulty
→
Set 2: CTA and 4:BUSW to ON.
Example 2: When the SC compressor is faulty
→
Set 3: CTS and 4:BUSW to ON.
Example 3: Backup operation is possible when the PC compressor is faulty.
→
Set 1: CTP and 4:BUSW to ON.
* Since the discharge pipe of the PC compressor does not have a check valve, check that the discharge refrigerant
for other compressor is not bypassed to the low-pressure side. If refrigerant has bypassed to the low-pressure
side, remove the PC compressor, close the discharge and suction pipes with pinches, and perform emergency
operation.
12. Backup Operation
NOTE
1
ON
2
1
ON
2
4 51
ON
2 3
4 51
ON
2 3
4 51
ON
2 3
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