Marty Singer is one of the few NCI trained in Carbon Monoxide safety and combustion analysists in our area. The “only” way to know if your furnace is safe and efficient is for a trained technician to measure the carbon monoxide oxygen and temperature of the flue gas.  A blue flame only indicates that the furnace is operating.  It doesn’t mean that it is safe or efficient.  Sadly, very few hvac technicians have invested in the tools and training necessary ensure your safety.

Above is a view of the junction between the primary and secondary heat exchangers.  This furnace was installed by a competitor and was approximately 1 year old.  The propane conversion kit was not correctly installed.  The customer requested maintenance, but had no idea how unsafe his furnace was.    This furnace had nice clean looking blue flames, but was producing thousands of ppm of carbon monoxide.  The recommended maximum is 100 ppm.  The furnace was red tagged and shut down until repairs could be made. 

Repairs included replacing the heat exchanger and draft motor assemblies.  Above are the combustion test results post repairs.  Note that the furnace is now producing 4 ppm of carbon monoxide in the flue gas compared to thousands prior to repairs.  

The sooted up section of the heat exchanger was not visible until the furnace was disassembled.  A visual inspection by a seasoned technician may tell much, but there is absolutely no substitute for fuel gas testing.  

Please click here for more information on why your furnaces needs combustion gas testing by a qualified technician equipped with the necessary tools.