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 externally switched on to disperse precipitation faster and to melt frost, or even snow and ice, on the dome in cold climates.

CVF4 is a low power, low maintenance ventilation unit. The only part that needs inspection is the removable air inlet filter, which should be checked at regular intervals and cleaned or replaced when necessary. 5 spare filters are included. A pulse output allows the fan speed to be monitored by a data logger TTL i/o port.

The airflow 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 cover material ensures that only half the heating power is needed compared to older ventilation units.

CVF4 is optimised to be used with Kipp & Zonen’s:

  • CMP and SMP 6, 10, 11, 21 and 22 pyranometers
  • CGR4 and SGR4 pyrgeometer
  • CUV5 and SUV-A, -B, -E and 5 UV radiometers

CVF4 can be mounted on the SOLYS Gear Drive and SOLYS2 sun trackers and the CM121C shadow ring.

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 heater on)
Operational temperature range -40 to +70 °C
Ventilation power 5 W continuously
Heating power 5.5 W externally switched
Heater induced offset < 1 W/m² (with CMP11 Pyranometer)



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