HVAC Duct & Accessories

VAV Control – Pressure Independent Type

Alfa Pressure independent VAV units are an innovative solution manufactured with the greatest precision and latest manufacturing techniques at Astic Industries. Alfa pressure independent terminal units are designed to control air volume flow rate for supply air on variable volume system. These units are designed to supply the air flow rate of conditioned air into an occupied zone in response to control signal from a thermostat or building management system. The components of the unit include an acoustically lined sheet metal box round inlet damper, sensor and rectangular outlet. Alfa PI VAV are connected with Nepcross cross flow differential sensor (Neptronic Make Canada) for measuring the air volume, which is located in the upstream section of the VAV chamber .The sensing points collectively average the primary air velocity pressure across the entire inlet area. These terminal units also incorporate control components, (VAV actuator, transformer), which are factory fitted and in house calibrated to ensure meet all design criteria . This enable the terminal to monitor desired air flow rate as indicated by the thermostat or input signal of 0-10V and compensate instantly for any changes in supply air pressure that might tend to alter the supply air volume – resulted as pressure independent variable air volume system.

Features And Benefits

  • Galvanized steel casing, mechanically sealed for low leakage construction
  • Circular damper blades for better flow management
  • Full range of opinion and accessories available (heating coils, attenuators…etc)
  • Available with imported Nertronic,Canada make of Nepcross Cross flow sensor,controller,Actuator and Thermostat CO2 sensor
  • Nepcross Cross flow sensors amplify sufficiently for differential pressure signals and minimize the white noise associated with the signal amplification
  • Dampers rotate in a low friction and long life Brass bearings
  • Control components encased in control panels
  • Acoustic lining with glass fiber wood suitable for air velocity up to 20 m/s
  • Flexible silicone gasket on damper blades for low leakage
  • Shaft indicator for damper position

Construction Details of Pressure Independent VAV

  • Air terminal casing ,inlets are manufactured from 22 G galvanized steel conforming to ASTM A 653,LFQ and G 90 coating
  • Damper shall have internal acoustic lining of 25 mm thick and 48 Kg/m3 density
  • Damper blades shall be manufactured from 0.9mm galvanized sheets with flexible gasket to ensure low The VAV package consists of 2 parts, namely the thermostat and the EVC which is a combination of an actuator and a controller which mounts directly to the damper jackshaft on the side of the VAV box
    • The EVC is available in two versions: a BTL listed BAC net application specific version (EVCB) or a stand-alone version (EVC)

      1. Amplify sufficiently for the differential pressure signal.
      2. Minimize the white noise associated with the signal amplification.

      This has been accomplished by Nepcross’s unique circular static pressure amplification probe and the geometry of the total pressure radial probes.

      The static pressure amplification circular probe collects the pressure signal from strategically located pressure ports along its outer diameter.

      The average static pressure signal (ASSP)is sent to the Low port of the electronic transducer. The ASAP is responsible for the amplification of the resulting Velocity Pressure Signal.

      The Neptronic VAV controllers have tailored curves also in the lower velocities which are more representative of the actual velocities rather than based on one point calibration and theoretical assumptions. That feature makes the total Neptronic assembly a perfect solution for modern VAV application.

      VAV Single Duct Controller & Actuator

      Nepcross Design Achieves Two Major Objectives

      Nepcross has been developed in order to give Independent Box Manufactures the ability to participate in the lucrative VAV pressure independent market.

      Now,the independent box manufactures have the choice to use the Nepcross with different VAV controllers or use the Nepcross with Neptronic Pressure Independent controllers.

      The Neptronic Pressure Independent Controllers (and corresponding thermostats) are available in free standing mode EVC or BAC net configuration mode EVCB.

      “Nepcross” Cross Flow Sensor leakage.

      • Damper bearing –brass bush 12mm
      • Aluminuim flow grid – Nepcross sensor (Neptronic Make Canada)
      • Supplied with imported Neptonic, Canada make controller ,Actuator and Thermostat
      • Grooved inlet connection tube for added rigidity and secure flex duct connections
      • Rectangular discharge with slip and drive cleat duct connection

Product Gallery

  • VAV Control – Pressure Independent Type

  • VAV Control – Pressure Independent Type

  • VAV Control – Pressure Independent Type

  • VAV Control – Pressure Independent Type