Continuous Emissions Monitoring Systems (CEMS) Maintenance – Analyzers


Continuous Emissions Monitoring Systems (CEMS) Maintenance – Analyzers

Continuous Emissions Monitoring Systems CEMS Maintenance: (a multi-part Series)

We continue our series on CEMS maintenance. This issue covers analyzer maintenance.


Both Dilution and Extractive CEMS utilize the same types of analyzers. While there are many different brands of analyzers on the market today, many of which utilize different measurement technologies, this edition will take a look at the broad spectrum of maintenance that nearly every analyzer requires for reliable continuous operation.

Quarterly P.M.’s

Quarterly preventative maintenance is relatively simple – a few simple inspections and procedures will make a big difference in the longevity of your
1. Filters should be changed every quarter. These are typically external in-line filters found on the back of the analyzer.
2. Chassis filters and/or fan screens should be cleaned every quarter to keep dust from accumulating and building up inside the case.
3. Analyzer statuses should be checked. Most modern analyzers have diagnostic readouts that can be used to ascertain problems. Check the statuses of temperature, voltages, coefficients, vacuum, and flow to determine problems (i.e. leaks in the system). Leaks often indicate a need to change a capillary or check the pump diaphram and valves.

In multiple analyzer systems, it’s important to initially determine if a problem is with a specific analyzer and not a “system” problem. Usually other analyzers will be affected by a system problem.

Typically, as a pump fails there is an indication in the sample pressure. It’s best to check the sample pressure reading every quarter and record it. Drastic changes in the sample pressure
are indicative of a failing pump.

Annual Maintenance

Once a year, it’s important to take some additional steps to maintain your analyzers in top working order:
1. Rebuild the pump with a diaphram and valve replacement kit. This is inexpensive insurance. Bearings should be inspected also. Instead of replacing bearings, it’s easier to simply replace the entire pump.
2. Replace capillary o-rings.
3. Depending on the type of analyzer, the optical bench or reaction chamber should be cleaned. Different processes can cause a build-up to occur on these parts. Where ammonia/urea injection is used, a white build-up can collect in not only the reaction chamber, but also the pump.
4. Clean the heat sinks and vacuum the inside of the analyzer. Dirt accumulation can create chamber instability and signal degradation.

Common Problems

The most common problems among analyzers is with mechanical failure of pumps and moving parts. Proper pump maintenance can keep these problems from becoming catastrophes.

The other common problem with analyzers is the development of leaks. This occurs at the capillary o-rings and in the Silastic tubing internal to the analyzer. Simple replacement resolves these problems.

Time to Upgrade your Existing CEMS Analyzers due to Age or Obsolesence?...please give Monitoring Solutions a call.
We supply name brand OEM analyzers for most manufacturers’ CEMS. Monitoring Solutions not only supply’s analyzers but can also assist with installation, start-up, and calibration.

With every analyzer we sell, we offer complete training and 24/7 telephone support for the first year. And of course, we support everything we sell with parts and in-house or on-site repairs if necessary.

Contact us today for budget pricing and/or quotes, and details on the newest replacement analyzers.

Jim Nowak


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