When any new oxygen sensor is removed from the sealed package, it can take anywhere from a few minutes to several hours for it to acclimate and the millivolt output to stabilize. We recommend waiting as long as practical before calibrating your rebreather with a freshly opened sensor.
Oxygen sensors are a consumable like a battery; their service life can vary considerably depending on usage, oxygen exposure and environmental factors. Three conditions are particularly notable for shortening the life of an oxygen sensor, regardless of brand.
- Impact - Inside the oxygen sensor are tiny wires and seals that are very fragile. Sensors subjected to g-force shocks explains why a new sensor will come out of the package DOA; high, low or zero millivolt output; or with erratic behaviors.
- Heat - The warmer the sensor, the shorter the life. That can happen during shipping or storage, especially in tropical climates. Their life can also be significantly shortened when the rebreather sits in the sun and gets very hot.
- Prolonged Oxygen Exposure - Leaving elevated oxygen mixtures in the breathing loop, which often happens following a calibration, will substantially reduce the life of a sensor. Heavy use of your rebreather will also shorten the life of the sensor.
As oxygen sensors reach end-of-life they can become unpredictable, causing problems that are sometimes difficult to diagnose. The expiration date printed on some sensors is not a guarantee they can remain in-service until that date; it is a caution against use after that date. In our opinion, there is not ANY in-the-field test or dive procedure that will properly validate a oxygen sensor for use beyond it's expiration date or recommended service life.