Heat Exchangers in Furnaces

Constantin

... I am wondering what kinds of materials are found in furnace heat exchangers. My impression from years past is that galvalume was the material of choice in furnaces, but perhaps that's based solely on observing non-condensing ones. Then again, I have seen so many pictures of rotted / rusted heat exchangers in furnaces that I wonder if any manufacturer is using a stainless material. Presumably, most of the rotten heat exchangers came out of non-condensing furnaces that operated in a condensing mode...

Based on the collective experience here, what kind of heat exchanger material do you normally find inside a non-condensing or condensing gas furnace? If a metal flue is used, what are the typical specifications for the material? Does anyone require the use of Al29-4c stainless flues or is 304/316 the norm?

Perry_3

AL294C

AL294C is used in condensing furnaces by at least some mfr's.

This is a ferritic form of Stainless steel - which means that it can rust (and is magnetic as well).

Here is the spec and application sheet for the product.

www.alleghenytechnologies.com/Ludlum/Documents/al294c.pdf

I note that this does not mean it is the only product used. Allegheny is of course tooting its horn about this product. I note their claim about over 2000 miles of it installed as condenser or HX tube material in Sea Water or Brackish water applications. While that is true... A similar suppreferritic with slightly different chemistry and really owns that market. Sea-Cure is installed in at least 20 times as many HX or Condenser applications as AL294C (I also note that 2000 miles is only about 10, 500 MW power plants).

Perry

d.wright

american standard hot water boiler

I am in need of a service manual for this american standard unit boiler Series- IBN-J3 Model # G-608 thank you in advance.