Hitachi PC-ARFG2-Z Installation & Maintenance Manual page 43

3. Backup operation in high load
If there is a difference between the room temperature and the setting temperature (※1), the standby refrigerant
systems start to operate.
System Example
System 1 System 2
Procedure of high load backup operation
System1 Operation
System2
Standby
Rotation Cycle Time
※1: Cooling/Heating: 2
※2: When the high load backup operation is finished, it turns into the rotation operation.
All standby systems are in operation.
22.1 Backup System Setting Items
1. Enable/Disable Backup System
This function is to enable/disable rotation operation.
Enable: Start rotation operation.
Disable: Rotation operation is invalid.(Default)
2. Rotation Cycle Time
Rotation cycle time can be set from "9 hours"(default), "24 hours", "48 hours", "72 hours" and "96 hours".
3. No. of Refrig. Systems to Operate
System Example
System 1 System 2
40
Standby
Operation
30Mins
o o o o
C to 5 C(2 F to 5 F).
System 3
High load backup startup
Operation
Standby
Operation
High load backup operation
System 4
22. Backup System Setting
2
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