Outdoor Unit Rotation - Daikin VRV RXYQ72-384XAYCA Service Manual

Special Control
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.
Startup control
Master Slave 1 Slave 2
Outdoor unit
Priority
rotation
A
Master Slave 1 Slave 2
Priority
Note(s)
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 displays on the outdoor unit main PCB for master unit, slave
unit 1 and slave unit 2 do not change.
103
Oil return operation
or defrost operation
Normal control
Priority Priority
1 2 3
Normal control
Priority Priority
3 1 2
Normal control
Master Slave 1 Slave 2
Outdoor unit
Priority
rotation
3
Any of outdoor
unit stops for a
period of 20
minutes or more.
Normal control
Outdoor unit
rotation
SiUS342004EB
Priority Priority
1 2
Master Slave 1 Slave 2
Priority Priority Priority
2 3 1
Part 4 Functions and Control
A