The Sunvou FeNO monitor does not require annual servicing as the sensor is replaced once your 100, 300 or 500 tests pack has been completed. 

The device performs an automatic purge cycle after each patient test; during this, it will draw ambient air through the tube, filter and analyser, then expel it, while simultaneously calibrating against the ambient nitric oxide (NO). This process ensures that the internal components remain dry, contaminant-free free and internally validated, ready for the next measurement. As a result of this process, the device will not require annual calibration.