Phason Natural Ventilation Control


Phason Natural Ventilation Control

SKU: VNCPNVC2 Categories: , ,

Control 12 and 24-volt curtain machines and heaters

The Natural Ventilation Control automatically controls the temperature in a room by operating a curtain machine and heater or furnace according to your programmed settings.

With 12 and 24 VDC models available, the NVC is the perfect solution for off-grid, battery-powered installations that use solar or wind power.

Controlling a curtain machine

  • When the temperature is within the idle band, the NVC-2 maintains the curtain position.
  • When the temperature rises above the idle band, the NVC-2 opens the curtain for the on duration and then pauses for the off duration.
  • After each off duration, the NVC-2 checks the temperature and then either opens or closes the curtain, depending on the temperature.

Controlling a heater

When the temperature is below the heat set point, the NVC-2 switches the heater on; when it is above the set point, the NVC-2 switches the heater off.



  • Automatic temperature-based control
    Range: -13 to 125°F (-25 to 51°C)
  • Programmable On and Off durations for the open and close relays
    1 to 900 seconds (up to 15 minutes)
  • Programmable Idle band
    1.0 to 10.0°F (0.6 to 5.5°C)
  • Programmable heater Hysteresis
    0.3 to 5.0°F (0.2 to 2.8°C)
  • Programmable High and Low temperature alarms
  • Two curtain relays (one open, one close)
  • Heater control relay
  • Alarm relay (for external alarm system)
  • Four-button keypad
  • Four-digit LED display
  • Programming and status LEDs
  • Manual override and test modes
  • Power-failure settings protection
  • Six-foot temperature sensor, extendable to 500 feet
  • Optional rain sensor
  • NEMA 4X enclosure (Corrosion-resistant, water-resistant, and fire-retardant)
  • 2 year warranty