CVF4-L Ventilation Unit for Pyranometers


The CVF4-L, manufactured by Kipp & Zonen, is a ventilator/heater for our CMP6CMP11, and CMP21 pyranometers. The ventilation unit improves the reliability and accuracy of the measurement by reducing dust, raindrops, and dew on the dome. The integrated heater can be used to disperse precipitation and melt frost, or even melt snow and ice in cold climates.

Read More


Cover of CVF4-L
CVF4-L Top View
CVF4-L Bottom View
Parts Kit for CVF4-L

Detailed Description

The CVF4 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 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 ensure that only half the heating power is needed to melt frost and snow compared to older ventilation units.

The CVF4 is meant to run continuously. The heater can either be switched on permanently for cold regions, or it can be switched by a Campbell Scientific datalogger to remove dew in the morning and then be switched off afterward. In that scenario, the heater could operate for a period before and after sunrise. This saves power in situations where power is limited, such as PV-operated systems.


Power Supply 12 Vdc, 0.9 A (with 5.5 W heater)
Operating Temperature Range -40° to +70°C
Ventilation Power 5 W (continuously)
Heating Power 5.5 W
Heater Induced Offset < 1 W/m2 (with CMP11)
Dimensions 35.5 x 23.0 x 12.95 cm (14.0 x 9.1 x 5.1 in.)
Weight 1.6 kg (3.5 lb) without cable



The CVF4 is compatible with the following pyranometers: CMP6, CMP11, and CMP21. 


The CVF4 is not comptible with CR200X-series dataloggers.


The 31153 Mounting Stand is used to fasten the CVF4 to a crossarm or pole via the CM220 right-angle mount or the 17953 Nu-Rail® fitting.

The CVF4 is not compatible with the CM245 mounting stand.

Listed Under

Common Accessory for the following products: