Description
Balance Intake Against Extraction From One Gavita Fan Signal
The Gavita FB1 EC Fan Balancer is a compact add-on module that works only with a Gavita EL1F or EL2F Master Controller – the fan-control models. It cannot run fans on its own: it takes the controller's fan signal and splits it in two: the Output runs your extraction fan exactly as the controller commands, while the Offset Output runs your intake fan at a lower speed you set on the dial, anywhere from 0% to 70% below the extractor. The controller keeps its automatic PID fan control for temperature and humidity, and the FB1 simply holds the gap between the two fans as their speed rises and falls.
Key Benefits
- Two fans from one control signal – one input feeds a direct output and an offset output.
- 0 to −70% offset on the intake fan, set on a single rotary dial.
- The controller stays in charge – the Master Controller still ramps both fans automatically, and the balance holds at every speed.
- Balances two identical fans – no need to buy a smaller intake fan or choke the intake duct to create negative pressure.
- Suits EC fans of any size; AC fans connect through Gavita's EFM1 module.
Over-Pressure and Escaping Odours
Carbon filters, silencers and long duct runs all slow the extraction side, so an intake fan matched to the extractor often pushes in more air than the extractor can pull out. The room drifts into positive pressure: tent walls bulge, warm humid air and odours leak out through every seam and gap, and airflow across the canopy turns uneven. Running the intake fan slower than the extractor keeps the grow room under slight negative pressure, so fresh air comes in where you want it and stale air leaves through the filter. The FB1 sets that difference once, on a dial, and keeps it in step with the controller from lights-on to lights-off.
How to Use
- Connect the FB1's Input to the fan output of your Gavita Master Controller (EL1F or EL2F).
- Connect the extraction fan to Output and the intake fan to Offset Output.
- Start with the dial at 0% and turn it towards −70% until the tent walls draw in slightly or a door shows a gentle inward pull.
- Leave the controller to manage temperature and humidity as normal – the offset follows every speed change.
- Running AC fans? Fit Gavita's EFM1 module to bring them under the controller.
Technical Specifications
- Brand: Gavita
- Model: FB1 EC Fan Balancer (UK)
- Type: Fan balancer / fan controller module
- Input: 1 – fan signal from a Gavita Master Controller
- Outputs: 2 – Output (follows the controller) and Offset Output
- Offset range: 0% to −70%, rotary dial
- Fan type: EC fans of any size; AC fans via the Gavita EFM1 module
- Compatible controllers: Gavita Master Controller EL1F and EL2F only (not the lighting-only EL1 or EL2)
- Fan control retained: the controller's automatic PID fan speed control
Frequently Asked Questions
Which Gavita controllers does the FB1 work with?
The fan-control Master Controllers, the EL1F and EL2F. The FB1 splits the controller's fan signal, so a lighting-only EL1 or EL2 – which has no fan output – cannot drive it.
Which fan goes on the offset output?
The intake fan. The extractor runs at the speed the controller asks for and the intake follows it, reduced by the offset you dial in, which keeps the room under slight negative pressure.
Can I use it with AC fans?
It is built for EC fans. AC fans need Gavita's EFM1 module before the Master Controller can control them.
How much offset should I set?
It depends on the filter, ducting and fan sizes. Start at 0%, increase the offset until the tent walls just pull inwards, and stop there – too much offset starves the room of fresh air.
Works Well With
