This product is no longer available and has been replaced by: CVF4-L. Some accessories, replacement parts, or services may still be available.
CVF3-L Ventilation Unit for Pyranometers


The CVF3, manufactured by Kipp & Zonen, is a ventilator/heater for our CMP6, CMP11, and CMP21 pyranometers. It helps keep the pyranometer's domes free from ice, dew, and dust.

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Detailed Description

The CVF3 uses a fan and inlet filter to draw clean air over the pyranometer’s domes. The fan runs continuously to reduce dust and dirt settling, to dissipate rain drops and to stabilize the dome temperature.

The CVF3 has both a 5 W and a 10 W heater. The 5 W heater raises the temperature of the dome slightly above ambient temperature to prevent the formation of dew and frost. The 10 W heater is used for more extreme climates to melt snow and ice.


Power Supply 12 Vdc, 1.3 A (with 10 W heater)
Operating Temperature -40° to +70°C
Ventilation Power 5 W (continuously)
Heating Power 5 W or 10 W
Heater Induced Offset < 1 W/m2 (with CMP11)
Diameter 22.4 cm (8.8 in.)
Height 12.9 cm (5.1 in.)
Weight without Cable 1.6 kg (3.5 lb)


Datalogger Considerations

Compatible Contemporary Dataloggers

CR200(X) Series CR800/CR850 CR1000 CR3000 CR9000X

Compatible Retired Dataloggers

CR500 CR510 CR10 CR10X 21X CR23X CR9000 CR5000 CR7X


CS300 LI200X LP02 CMP3 CMP6 CMP11 CMP21


The 27084 mounting stand is used to fasten the CVF3 to a CM220 Right-Angle Mounting Bracket or a 17953 1 in. by 1 in. NU-RAIL. The CM220 or 17953 is then attached to a mast or crossarm. The CVF3 is not compatible with the CM245 mounting stand.

Power Considerations

The 10 W heater’s current drain is approximately 850 mA at 12 Vdc, and the 5 W heater’s current drain is approximately 420 mA at 12 Vdc. The ventilator draws an additional 5 W of power at 12 Vdc. These power requirements are large compared to most Campbell Scientific products. Because of this, the CVF3 should be connected to the 21326 Power Net 5 A Power Supply and the 7321 Crydom Relay.

The Crydom relay allows the heater power to be controlled by the datalogger program and thus reducing power consumption. For example, the datalogger program can turn on the heater only when the light level falls below 20 W/m2 or, if a measurement of air humidity is available, when the dew point of the air falls to within 1ºC of the sensor body temperature.

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