Daikin Aurora Series, Service Manual, Page: 77 / 333

SiUS341802E Special Control
Functions and Control 64
7.4 Outdoor Unit Rotation
In the case of multi outdoor unit system, this outdoor unit rotation prevents the compressor from
breaking down due to unbalanced oil level between outdoor units.
Details of outdoor unit rotation
In the case of multi outdoor unit system, each outdoor unit is given an operating priority for the
control.
The operating priority of outdoor units is changed by outdoor unit rotation. The outdoor unit rotation
prevents unbalanced oil level between outdoor units by eliminating the long stop of compressors
during partial load.
Timing of outdoor unit rotation
• At the beginning of the startup control, or;
• After oil return operation, or;
• After defrost operation, or;
• One of the outdoor units is stopped for 20 minutes or more (only in cooling).
Example) The following diagram shows outdoor unit rotation in combination of 3 outdoor units.
Note:
∗
“Master unit”, “slave unit 1” and “slave unit 2” in this section are the names for installation.
They are determined in installation work, and not changed thereafter. (These names are different
from “master unit” and “slave unit” for control.)
The outdoor unit connected the control wires (F1 and F2) for the indoor unit should be designated
as master unit.
Consequently, The LED display on the outdoor unit main PCB for “master unit”, “slave unit 1” and
“slave unit 2” do not change.
Normal operation Normal operation
Normal operation Normal operation
Master Slave 1 Slave 2
Master Slave 1 Slave 2
Master Slave 1 Slave 2
Master Slave 1 Slave 2
A
A
Startup control
Outdoor unit
rotation
Outdoor unit
rotation
Outdoor unit
rotation
Priority
1
Priority
1
Priority
2
Priority
2
Priority
3
Priority
3
Priority
1
Priority
2
Priority
3
Priority
3
Priority
1
Priority
2
Oil return operation
or defrost operation
One of the outdoor
units is stopped for
20 minutes or more