Fujitsu General Australia

Overview

When multiple indoor units are connected in a group configuration and each has a wired remote controller, it is necessary to assign one controller as the master controller.
The master controller governs mode selection (heating/cooling) and ensures consistent operation across all connected indoor units.

If no master controller is set, mode selection priority defaults to the controller that sends the first operation command, which may lead to inconsistent control or mode conflicts.

1. Application

This setting applies to:

• Systems with multiple indoor units connected under one RB unit (group connection).

• Systems where each indoor unit has an individual wired remote controller.

• VRF systems such as VR-II, VRF-II series, J-IIIL, and J-IIS models.

2. Key Function

The Administrative Indoor Unit (Master Controller):

• Determines whether the system operates in Cooling or Heating mode.

• Overrides mode commands from other controllers in the group.

• Provides system-wide coordination when multiple controllers are in use.

3. Correct and Incorrect Configurations

Example 1 (Correct Configuration)

All indoor units are connected to the same RB unit, with one wired remote controller designated as the master.
This allows coordinated group operation and consistent mode control.

Example 2 (Prohibited Configuration)

Indoor units connected to different RB units cannot share a single master controller.
In this setup, administrative control cannot be established, and group mode synchronization will fail.

(See diagram on page 1 for connection layout reference.)

4. Setting Method (Touch Panel or Standard Wired Remote Controller)

Step 1 – RB Unit Setting (VR-II Series)

1. Locate the DIP switch (SET2) on the RB unit.

2. Set as follows:

   • SET2-1: OFF

   • SET2-2: ON

3. This prioritizes the “Administrative Indoor Unit” function within the RB unit group.

4. Refer to the RB Unit Function Setting section for confirmation.

Step 2 – Outdoor Unit Setting (All VRF II Series)

Set the outdoor unit function to “Priority given to Administrative Indoor Unit.”
Refer to the outdoor unit function settings for the correct switch or software configuration.

Step 3 – Wired Remote Controller Setting

Using the touch panel or standard remote:

1. From the Initial Setting menu, select Master Indoor Unit Setting.

2. When prompted, select Set → confirm with Yes.

3. The selected indoor unit becomes the master.

4. To remove a master setting, select Reset (only available when the indoor unit is stopped).

Important:
Before assigning a new master indoor unit, cancel the existing master setting first.
A new indoor unit cannot be registered as master while another is still assigned.

(Refer to page 2 of the document for example interface screens.)

5. Quick Method (Wired Remote Controller Button)

If using a standard wired controller:

1. Stop indoor unit operation.

2. Press and hold the MODE button for 5 seconds.

   • Display lights will indicate:

     • Not set as administrative unit

     • Set as administrative unit

3. Release the button to select the desired status.

4. Repeat the process to cancel the administrative indoor unit setting.

The display will blink during setting and return to normal after 20 seconds.
“Administrative Indoor Unit” must also be enabled in the outdoor unit priority settings.

(See page 3 for indicator examples.)

6. Operational Note

When operating under group control:

• The cool/heat mode changeover is determined by the indoor unit with the smallest remote controller address number.

• The master wired controller is responsible for maintaining consistent mode operation across the RB group.

(Refer to diagram on page 4 for temperature control logic.)

7. Summary Table

8. Common Issues