General Assist Technical Reference
VRF Energy-Saving Features
Occupancy control, peak power limiting, ventilation interlock and low-noise operation
For Fujitsu General / AIRSTAGE VRF applications
Fujitsu General VRF systems incorporate a range of energy-saving functions designed to reduce unnecessary operation and help control power consumption while maintaining comfort. Available functions can include automatic shutoff, peak power control, ventilation interlock, human sensor operation, keycard interlock and nighttime low-noise settings.
Important: Available functions, wiring methods, function numbers and setting ranges vary by VRF series, outdoor unit and controller. Confirm the applicable installation and technical documentation before changing settings or connecting external devices.
1. Energy-saving features overview
| Feature | How it works |
|---|---|
| Automatic Off Function | Automatically turns the system off when no occupancy is detected for a set period. |
| Peak Power Consumption Control | Limits total power consumption to a preset level to help control maximum demand. |
| Ventilation Interlock | Coordinates air-conditioning operation with an external ventilation system. |
| Human Sensor Integration | Uses occupancy detection to adjust operation when a room is occupied or unoccupied. |
| Keycard Interlock | Allows air-conditioning operation to be linked to a room keycard or external occupancy contact. |
| Nighttime Low Noise Mode | Provides a reduced-noise operating mode for selected nighttime or off-peak operating periods. |
2. Typical applications
Office buildings: Automatic shutoff can reduce unnecessary operation after hours or when meeting rooms and other spaces are unoccupied.
Hotels and accommodation: Keycard interlock can stop or change air-conditioning operation when guests leave a room.
Retail and commercial sites: Peak power control can be used to manage system demand during higher-load periods.
3. Setting up energy-saving functions
Automatic Off Function
- Access the applicable system or controller settings.
- Select the required automatic shutoff function.
- Set the required no-occupancy period and associated operating behaviour.
Peak Power Consumption Control
- Access the applicable outdoor unit PCB function settings.
- The source information identifies Mode No. 03 for peak power control.
- Select the required capacity limit. The source information references settings ranging from 40% to 100%.
Human Sensor Integration
- Connect the applicable human sensor or occupancy input to the supported indoor unit connection.
- Confirm the required wiring arrangement and any applicable DIP switch or function settings.
- Test occupied and unoccupied operation after configuration.
Keycard Interlock
- Install the required keycard reader or external contact arrangement.
- Connect the external input using the applicable external input kit or supported terminals.
- Test keycard inserted and removed states to confirm the required ON/OFF response.
Nighttime Low Noise Mode
- Access the applicable outdoor unit PCB settings.
- The source information references Mode No. 40 for Quiet Priority and Mode No. 41 for Capacity Priority.
- Select the mode appropriate to the site operating requirements.
Commissioning check: After making changes, confirm normal heating and cooling operation and test the relevant external input, occupancy or power-limiting function under controlled conditions.
4. Reference images
Always confirm model-specific availability, wiring, function numbers and setting ranges against the applicable Fujitsu General / AIRSTAGE technical documentation before installation, configuration or commissioning.