19Instruction Manual - CVF4Regular inspection of the CVF4 is advised. Depending on the location (air pollution) this can be monthly or yearly. When on sitefor inspection of other instruments it is advised to check the CVF4 filter.At the same time radiometer levelling and desiccant can be checked. For access to the desiccant the 2 mounting nuts have to beloosened and the top cover taken off.When replacing the cover, make sure it is placed correctly. This can best be done by checking the opening around the radiometer,this should be evenly spaced.Tip: When the tacho output is logged with the radiometer data, the performance of the ventilator can be remotely checked.Refer to radiometer instruction sheet for maintenance instructions.Regularly inspect the fan inlet by unclipping the cover.For optimal air flow, make sure the diagonal line on the cover is in line with the ventilator part (see above drawing).The filter cover clicks back on the ventilator.Clean or replace filter every 6 months.The interval strongly depends on the location and pollution of the air. Discolouration or pollution of the plastic cover will notaffect the proper operation of the radiometer. (the radiometer can not ‘see’ the CVF4 cover). Cleaning of the cover can bedone with water and a brush or cloth.4. Maintenance123213