VarioflowBOX COMF EVO 400-MP variable airflow controller

Functions

Variable air volume controller (VAV controller) is used for autonomous control of the amount of ventilation air of one zone in central ventilation systems.

Construction

The VarioflowBOX COMF EVO VAV controller consists of a pair of tubes (supply and extract) equipped with rails for anchoring to the supporting structure, an electrical switchboard with a VARIOSU 24-10 power supply unit located on the rails of one of the tubes and a small box containing boost timers (Varioboost 24 VAC). For the Varioboost 24 VAC, a DIN rail is provided at the electrical panel for mounting it; alternatively, it can be mounted in a residential panelboard. Both tubes are fitted with a lip seal for connection to the circular pipe. The individual parts are made of galvanized steel sheet. The design differs for dimensions 100 to 160 and 200 to 400. The former have actuators located together with control dampers inside the tubes and the air flow is measured by means of a thermoanemometer. The second design uses flow measurement based on the pressure differential measured by a probe inside each tube. The actuators in this variant are mounted on the casing and are equipped with a pressure air flow sensor. The control valves located in each of the tubes have class 2 leakage according to EN 1751 when closed, except for DN 100, which is only class 3.

Electro

The supply voltage is 1x230 V/50 Hz. The VarioflowBOX COMF EVO is equipped with a 230 V/24 V power supply unit with a connection cable terminated in a 230 V fork with protective conductor. The air flow can be controlled by a 0-10 V analogue signal or by two potential-free contacts (BOOSTs). The BOOST function timer is fixed at 7 or 15 minutes. The regulated air quantity in the inlet tube is the same as in the outlet tube (INPUT = OUTPUT). The degree of protection of the electrical switchboard is IP44. The communication interface for the control system can be selected between Modbus RTU or MP-Bus for dimensions 200, 250, 315 and 400. For dimensions 100, 125 and 160 only MP-bus is available.

Mounting

Wall or ceiling mounted with airflow directions horizontal or vertical. It is necessary to observe the airflow directions shown by the arrows on the tubes. Adequate access must be provided for servicing and maintenance of the controller. In front of the VAV controller, a straight piece of pipe must be provided in the direction of air flow before entering the tubes in the following lengths:
- 1x D for DN 100, 125 and 160
- 2x D for DN 200, 250, 315 and 400

Conditions of operation

Maximum air velocity for dimensions 100, 125 and 160 is 7 m/s, for dimensions 200, 250, 315 and 400 is 12 m/s. The minimum air velocity for dimensions 100, 125 and 160 is 0.3 m/s, for dimensions 200, 250, 315 and 400 is 2 m/s. In the factory, it is possible to set airflow ranges different from the standard ranges listed in the technical parameters table (Vmin and Vmax ranges must be specified when ordering). The maximum possible pressure difference before and after the damper is
900 Pa. The temperature range of the conveyed air should be from 0 °C to + 50 °C and the maximum relative humidity of the flowing air up to 95 % (condensation on the surface or inside the tubes must be prevented). The air flowing through the tubes must be free of adhesive and abrasive impurities to prevent fouling of the flow rate or pressure sensor probes and the control damper.

Accessories

Individual controllers are not required for the VarioflowBOX COMF EVO VAV controller. Please refer to the Control Options section for more detailed information on the controllers.
- Belimo wall-mounted controllers:
- CRP24-B1
- CRA24-B1P
- CRA24-B3
- ABB wall-mounted controllers:
- Design Zoni
- Design Swing (L)
- Design Tango
- Design Levit (M)
- Design Time (Arbo)
- Design Future linear
- Design Solo (carat)
- Design Busch-axcent
- MSKM-KB damper for zoning on the exhaust branch (priority extraction from the kitchen)