Combustion controlled condensing boilers

February 2017
– December 2018

The integration of renewable gases (hydrogen, biomethane…) is of increasing importance in view of the rising need to join efforts in order to mitigate greenhouse gas emissions. In this context, gas quality and the definition of acceptable ranges of variation was in intensive discussion and a central goal of European standardization work. For this reason, a growing number of manufactures developed and brought to market integrated self-regulating components for condensing boilers. 

The technology of combustion controlled condensing boilers-CCCB was first introduced in the market in 2001.This technology mainly relies on the technology of ionization signal in combination with a smart control including also the fail-safe function. Moreover, reliable market data from Germany revealed an already high and growing share in sales since few years already.  

However, the knowledge in the technical public and from independent lab- and field investigation seemed to be poor. With the purpose of producing a state-of-the-art  review of self-regulated gas boilers able to cope with gas quality variation, this GERG project was initiated. 

Each sponsor participated with a fee of 8000€ and the total cost of the project was estimated in 190000€. 

This project was organised in two different phases.  

  • Phase I comprised a study of the technology and market for combustion-controlled condensing boilers that lasted from February to October 2017.  
  • Phase II tested their performance and compared it with conventional condensing boilers​ and lasted from October 2017 to December 2018.  

Both phases are now complete. Literature research in Phase I revealed an immense amount of publication on different sensor technologies, gas quality studies and very specific details, but a lack of independent lab tests and fields test of CCCB technology. Tests in Phase II revealed that the technology used to enhance the condensing boilers is highly effective. Gas appliances with the technology could function over a much wider range of the Wobbe index than that currently stipulated in the EU harmonisation process. Boiler performance (e.g. efficiency, emissions) remains constant over the range examined.   

This project has now ended, and the final report has been submitted. It brought important information not only to end user customers, installers and manufacturer but also for the discussions within the standardization process of gas quality in Europe. 

See below the management summary and final report for more information.