How Frequently Should I Measure My CMS Levels and What's the Process?

To ensure optimal performance of your nitrogen generator, we recommend checking the CMS (Carbon Molecular Sieve) levels in your sieve beds every 18–24 months. Over time, material can settle or be lost, leading to reduced efficiency.

Common symptoms of CMS loss include:

• Nitrogen purity falling out of specification

• CMS “dusting” observed in process valves or downstream filtration

Steps to Check CMS Levels:

1. Turn off your nitrogen generator.

2. Close the outlet valve on the generator to isolate the system.

3. Depressurize the sieve beds:

   • Open the front-facing ball valves on each side of the unit. These valves typically have yellow handles and are located next to pressure gauges.

   • Keep these valves open for the entire inspection process.

   • On smaller units without these valves, relieve pressure by carefully pulling up on the safety relief valve located on top of the sieve bed.

4. Remove the top plugs from each sieve bed:

   • Start with a quarter turn to release any residual pressure.

   • Once pressure is fully released, remove the plugs entirely.

5. Measure the CMS level:

   • Use a tape measure and measure from the top of the threads down to the point where the tape contacts the CMS material.

   • If there is a noticeable gap between the top of the CMS and the inspection port, the bed may need to be topped off.

6. If additional CMS material is needed:
   Contact Us to request a quote.

7. Need help refilling CMS?
   Step-by-step instructions can be found How to "Top Up" CMS.