SR-1 CO2 Analyzer Calibration Process

Below you will find a video that walks you through the calibration process of the SR-1 CO2 Analyzer.

Frequently Asked Questions

Most frequently asked questions and answers

The SR-1 detection system holds calibration for a few weeks to a couple of months depending on how many samples you are running.  However, we typically recommend recalibrating following maintenance of your SR-1, such as changing of the desiccant tube assembly.  If you are running a QC Check soil, then you should recalibrate if your readings are greater than +/- 10% of mean value. In addition, you should check your calibration at least once per week using one of the provided or purchased calibration gases by following the procedure outlined in the User’s Manual.

The SR-1 software provides a readout for moisture content in parts per trillion (ppt).  The value for moisture should read below 10 ppt, but when the readout is consistent at 10 ppt or above, then it is time to change the desiccant.

Yes, these can be washed and allowed to dry prior to reuse.  If the filters are starting to fall apart or become plugged, then they need to be replaced.

This should be changed annually or if changing the desiccant tube assembly does not result in lower moisture readings.  In addition, you should change this filter if you suspect the system is plugged and changing the desiccant tube assembly does not fix the problem.

The optical bench is designed to last over 2 years with continuous operation, which equates to nearly 18,000 hours of life expectancy.  

The optical bench can be purchased directly from LI-COR Biosciences and replaced with little effort right in your lab. You may also contact us at and we will work with you to get your SR-1 back up and running.

The pressure should be between 90 and 93 kPa.  If the pressure is too high, try packing the desiccant tube more tightly.  In contrast, if it is too low, then refill the desiccant tube loosely. If the problem persists contact

The desired flow rate is between 0.5 and 1 L per minute without a jar attached.  Slight adjustments can be made using the adjustable flow meter on the front of your SR-1 instrument.

This is normal because of slight pressure changes when the system goes from an open to a closed environment.

The SR-1 software is triggered to look for a peak based on a change in pressure when hooking up a jar.  If the jar is leaking, then the pressure won’t change and you will not record the peak. If this happens, the sample needs to be re-run. If the pressure appears to be changing as normal and you still do not get a reading, please contact us at

This can be caused by less than optical flow rates.  Try changing the desiccant tube assembly, recalibrating and running another sample.  You can also try adjusting the flow rate using the adjustment meter on the front of your SR-1.  If the problem persists, please contact us at

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