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Advanced digital CEMS analysis from the 4900 Multigas

The 4900 Multigas is a high-performance CEMS analyzer designed for a wide range of multi-gas measurements.

A comprehensive solution for analysis of multiple flue gas components

Specifically designed for Continuous Emissions Monitoring (CEMS) of flue gas, the SERVOPRO 4900 Multigas can deliver up to four simultaneous gas stream measurements. It combines Servomex’s leading-edge sensing technologies with a modern digital platform, for next-generation performance at a low cost of ownership.

The 4900 Multigas is backwards-compatible with existing 4900 installations and uses the same reliable measurement technology, providing trusted gas analysis combined with the advanced digital communications required by modern systems.

Luke Purdie
Product Manager

A complete monitoring solution for CEMS gas analysis

For industries and processes including power generation, petrochemical, refining, waste incineration, iron and steel, pulp and paper, and cement manufacture, continuous emissions monitoring is a regulatory requirement.
The solution must be capable of offering the highest sensitivity and accuracy when dealing with multiple measurements for pollutants and greenhouse gases. No matter what your application needs, you’ll want a solution that’s easy to install and operate, while delivering attractive affordability. And we don’t believe you should have to compromise.

A no-compromise solution

The 4900 Multigas meets all your CEMS requirements through a specific design and feature set optimized to continuous flue gas emissions monitoring applications. This compact, small-footprint analyzer integrates effortlessly into your established systems and, when used with the correct sampling system, delivers high grade multi-gas monitoring of criterion pollutant and greenhouse gases (% O2, CO2 and CO, plus ppm SO2, NO, CO, CH4, and N2O). The 4900 Multigas combines three sensitive and highly stable non-depleting technologies to deliver unsurpassed measurements you can rely on – Paramagnetic, Single Beam Single Wavelength NDIR and Gas Filter Correlation NDIR. In addition to its performance, the 4900 Multigas also comes with analog/serial outputs, with digital communications protocols Serial Modbus, PROFIBUS, and Ethernet (Modbus TCP/IP) for added flexibility in configuration and set-up. An external NOx converter can be used to analyze and speciate NOx, NO and NO2.

Simple maintenance and reduced ongoing costs

Added to its considerable measurement performance and stability, the 4900 Multigas delivers highly attractive cost reductions over product life. Not only is this device optimized for easy set-up and flexible integration, but an auto-calibration function permits easy, low-cost remote calibration. The 4900 Multigas allows diagnostic values to be exported for early detection of problems for preventative, or even predictive maintenance.

Man with Servomex System components

Building a CEMS system? Let us help

If you’re putting together a system for continuous emissions monitoring, our team can provide the added expertise you need. Get in touch today for optimum project performance.

Ready to buy? Here’s how it works

It’s easy to find the product you need for your application with Servomex

Servomex UK technical center


Get in touch to tell us what you need and the application you plan to use it for

Servomex Gas System Schematics


Our expert team will help you select the right product package, ensuring you have the accessories and support to get the best performance from your analyzer

Woman Assembling Sensors


Your analyzer will be assembled in one of our state-of-the-art engineering centers and rapidly dispatched to your site

The benefits of next-generation CEMS analysis

Providing up to four simultaneous measurements, the 4900 Multigas delivers a highly attractive, cost-effective package for flue gas analysis

Meets key certifications

Combined with a suitable sampling system, the 4900 Multigas provides unparalleled MCERT (EN 15627-3) and QAL1 (EN14181) measurements of criterion pollutants and greenhouse gases.

Ready for systems integration

Designed to be compact and robust, the 4900 Multigas requires minimal cabinet space and can be easily integrated into other systems, helping to reduce installation costs.

An affordable solution

The 4900 Multigas has low operational requirements, facilitated through long calibration intervals by ultra-stable, high performance sensing technologies and auto-calibration capabilities.

Unrivalled performance

  • Non-depleting sensors for ultra-stable, accurate and selective measurements
  • Manufactured by Servomex – over 70 years’ experience innovating and pioneering gas analysis and thousands of units used in the field every year


  • Provides a complete continuous emissions monitoring solution for flue gas analysis
  • Ideal for criterion pollutant and greenhouse gas monitoring: % level O2, CO2 and CO, plus ppm level SO2, NO, CO, CH4 and N2O
  • Continuous multi-gas monitoring
  • Digital communications for remote access: RS232/RS485 Modbus, PROFIBUS and Ethernet (Modbus TCP/IP)

Easy to use

  • Small and compact: designed for simplified integration into existing systems and easy fit into a cabinet
  • Auto-calibration facility
  • Intuitive-use icon-driven color touchscreen for easy device interaction and configuration
  • USB serial port for data logging and software upgrades

Low cost of ownership

  • Reduced ongoing operational needs facilitated by auto-calibration function
  • Extended calibration periods from ultra-stable, industryleading Paramagnetic, SBSW IR and GFx IR sensing technologies

Benchmark compliance

  • In compliance with Low Voltage, EMC and applicable EU directives
  • Certified to MCERTS (EN 15627-3) and QAL 1 (EN 14181) – O2, SO2, CO and NO

The 4900 Multigas delivers highly accurate monitoring of criterion pollutants, greenhouse gases and reference oxygen

Gas Measurement
Oxygen (O₂)%
Carbon monoxide + methane (CO + CH₄)%, ppmv
Carbon dioxide (CO₂)%
Methane (CH₄)ppm
Nitrous oxide (N₂O)ppm
Nitric oxide (NO)ppm
Sulfur dioxide (SO₂)ppm


Paramagnetic Infrared Gas filter correlation
SERVOPRO Servomex 4900 Multigas


  • EN 61010-1: Safety requirements for electrical equipment for measurement, control and laboratory use
  • EN 61326-1: Electrical equipment for measurement, control and laboratory use
  • EMC requirements
  • Installation Category II rated in accordance with IEC664
  • Certified to MCERTS (EN15627-3) and QAL 1 (EN14181) – O2, SO2, CO and NO

Schematics (select to expand)


132.5mm (5.2”) high
481.6mm (19”) wide
544.2mm (21.4”) deep

With expansion chassis, height is 265.5mm (10.5”)


Main unit: approx. 14kg (30.9lb)

Expansion chassis: approx. 13.7kg (302.2lb)
(weight dependent on number and type of sensors used)

Get the detailed specifications

“For in-depth specifications you’ll want to download our technical datasheet which includes information on technology, performance, operating environment, sample conditions and compliance along with technical drawings and top-level benefits and applications.”

Luke Purdie
Product Manager

Our resource pack download has everything you need to know

“Download the 4900 Multigas resource pack for all the information you’ll need for an informed purchase decision. It reveals how the analyzer will improve your process performance, and includes the product brochure and manual.”

Luke Purdie
Product Manager

Manuals and brochures

Download the manual and brochure for this product to discover its features and benefits. You’ll also get all the technical data you need, along with information about installation and operation.

ES Magazine Issue 29 Clean Air

ES Magazine Issue 29 Clean Air

SERVOPRO 4900 Multigas Quick Start Guide

SERVOPRO 4900 Multigas Quick Start Guide

SERVOPRO 4900 Multigas Operator Manual

SERVOPRO 4900 Multigas Operator Manual

SERVOPRO 4900 Multigas Product brochure

SERVOPRO 4900 Multigas Product brochure

See for yourself

Our videos give you the chance to watch our products in action and hear from our experts. You can also see our analyzers unboxed, and find out more about our solutions for key applications

Unboxed: the SERVOPRO 4900 Multigas

Watch as our expert unpackages this high-performance CEMS analyzer 

The SERVOPRO 4900 Multigas

Discover how our digital CEMs analyzer measures up to four gas components 

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