CVF4 Ventilation Unit

  • Improves accuracy of measurements
  • Easy to install and low maintenance
  • Pulse output to monitor performance
  • Reduces Zero offset A
  • Improved flow over the top of the dome
  • Can be used under all weather conditions
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CVF4 Ventilation Unit

Ventilation of radiometers improves the reliability and accuracy of the measurement by reducing dust, raindrops and dew on the dome. With thermopile-based instruments ventilation stabilises the temperature of the radiometer and suppresses thermal offsets. The integrated heater can be used to disperse precipitation and melt frost, or even melt snow and ice in cold climates.

CVF4 is a low power, low maintenance ventilation unit. The only part that needs maintenance is the removable air inlet filter, which should be checked at regular intervals and cleaned or replaced when necessary.

The flow that the CVF4 creates is unique. At the top of the pyranometer dome the flow is very high and it swirls to improve the air distribution over the dome. The position of the heaters and the new cover material ensures that only half the heating power is needed to melt frost and snow compared to older ventilation units.

CVF 4 is designed to be used with Kipp & Zonen’s:

  • CMP / SMP pyranometers
  • CGR4 / SGR4 pyrgeometer
  • CUV5 / SUV5 total UV radiometer

CVF4 can be mounted on the 2AP and SOLYS2 sun trackers and the CM121C shadow ring.

CVF4 replaces the successful and widely used CVF3 ventilation unit.

For instruction on the installation of a CVF4 ventilation unit on a SOLYS2 sun tracker, please watch this video.



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Power supply 12 VDC, 0.9 A (with 5.5 W Heater)
Operational temperature range -40 to +70 °C
Ventilation power 5 W Continuously
Heating power 5.5 W
Heater induced offset < 1W/m² (with CMP11 Pyranometer)