FRA is a measuring unit with a measuring cross, which is used for measuring volume flow in rectangular ducts.
FRA is equipped with Belimo VRD3, which provides an output signal that is proportional to the volume flow.
The FRA flow measuring unit and a DJP type damper put together will form a complete VRA unit. VRA is used for volume flow regulation in rectangular ducts, either for constant volume flow with step control, e.g. controlled by a switch or clock, or for variable volume flow, where the volume flow varies between a defined minimum and maximum limit. The actual volume flow is determined by a control signal from, for example, Regula Combi, BMS or another FRA/VRA.
The FRA needs a certain distance of straight duct before the unit and this has to be observed to obtain a stable and accurate airflow regulation.
- Requires minimal initial pressure (Less than 20 Pa at Vnom)
- Output signal indicates actual volumeflow