Natural Ventilation Control DC

Model: NVC-2-12 and NVC-2-24

Natural Ventilation Control DC

Model: NVC-2-12 and NVC-2-24
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.

See example

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.

AC-powered model

An AC-powered model, NVC-2, is also available.


SKU: NVC-2-12 and NVC-2-24 Category:
  • 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)
  • Limited warranty
  • Incoming power
    NVC-2-12: 12 VDC, 250 mA
    NVC-2-24: 24 VDC, 125 mA
  • Open/close/heat relays
    12 A at 30 VDC
  • Alarm relay
    2.0 A at 30 VDC, resistive load
    1.0 A at 30 VDC, inductive load

Phason Rain Sensor

The Phason Rain Sensor detects rainfall and allows you to automatically close the curtain when it is raining.

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Manual Override Box

The Manual Override Box increases the load handling capability of your control's relays and provides an external disconnect.

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Temperature Sensors

Additional temperature sensors allow you to use 4-zone temperature averaging. Probes are available several lengths and can be extended up to 500 feet using extension cable.

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Display kit (NVC-2-12: K331003)

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Display Kit | NVC-2-24

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Bottom Board Kit | NVC-2-12

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Bottom Board Kit | NVC-2-24

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