Corrosion-Resistant Condensing Heat Exchangers: Suggested Practices for Appliance Design and Materials Selection. Technology Bulletin

摘要

Design and materials considerations are developed to limit corrosive attack of condensing heat exchangers in gas appliances. Materials research shows that common grades of stainless steel are susceptible to severe corrosion attack if there is an appreciable level of chloride present in the condensate. Design considerations focus on the areas of combustion air supply, non-condensing portions of the heat exchanger, condensing heat exchanger, and condensate handling. The study develops suggestions to reduce the corrosivity (concentration) of the condensate, limit corrosion from evaporating condensate, limit concentrating from scrubbing, and maximize condensate dilution.