General Assist Technical Reference
Service Bulletin VRF-0160
Custom Auto Function Problem
Product: VRF Indoor Units | Bulletin issued: 25 April 2018
A malfunction can occur with the Custom Auto function on certain newer VRF indoor units when operating priority is assigned to an administrative indoor unit.
Issue summary
The service bulletin advises that a portion of newer VRF indoor unit models, which began shipping in December 2017 for the North American market, may malfunction when using the Custom Auto function.
Occurrence condition: The issue is associated with configurations where priority is given to the administrative indoor unit.
Heat pump system setting
For a heat pump system, set the outdoor unit operating mode priority using Function Setting Mode F2.
| Setting | Function | Remarks |
|---|---|---|
| 21-02 | Priority given to administrative indoor unit | Priority is given to the operating mode of the administrative indoor unit selected by the wired remote controller. |
| 21-00 | Factory setting | Priority is given to the first command. The bulletin states the trouble does not occur with this default setting. |
Required setting to reproduce the affected condition: Outdoor unit Function Setting Mode F2 = 21-02.
Heat recovery system setting
For a heat recovery system, configure SET2 on the RB unit controller PCB as follows:
| SET2-1 | SET2-2 | Description |
|---|---|---|
| OFF | ON | Priority is given to the operating mode of the administrative indoor unit selected by the wired remote controller. |
Factory setting: SET2 switches are ALL OFF. Under the factory setting, priority is given to the first command and the bulletin states that the trouble does not occur.
Technician quick reference
| System | Affected priority configuration | Factory/default configuration |
|---|---|---|
| Heat pump | F2 setting 21-02 | F2 setting 21-00 — first command priority |
| Heat recovery | RB unit SET2: 2-1 OFF / 2-2 ON | ALL OFF — first command priority |
Important: This article reflects the information shown on page 1 of Service Bulletin VRF-0160. Do not change system configuration solely from this summary where the complete bulletin specifies additional affected models, conditions or corrective actions.
Reference: Service Bulletin VRF-0160 — Custom Auto Function Problem — issued 25 April 2018.
