Vapor and combustion by-products combine to create highly acidic condensate. This restricts the types of metal used in condensing appliances for hydronic heating. Prior practice was to use building location, lighting design and other factors and 20°F ΔT calculations for designing hydronic heating systems. This led to systems designed for worst case scenarios, resulting in overcapacity and wasted energy. With the emphasis on Green design, systems should and can be designed to building load. New technology in controls, segmented systems and lead lag capability allow systems to only use the energy needed, to provide the appropriate amount of heat.

The more industrial boilers are used, the more potential for corrosion exists, resulting in shortened appliance life. An extremely effective method for reducing corrosion is water treatment. This presentation covers the typical metals found in boiler systems, system operation, corrosion causes and effects, focusing on the effects of corrosion on hydronic heating systems. Systems with and without water treatment through conventional and green corrosion inhibitors are examined along with options for maintaining system efficiency.

This presentation covers venting requirements for high efficiency hydronic heating systems, including venting basics as well as special gas venting systems for Category II, III & IV. Appliance manufacturer’s requirements and proper system design will be discussed along with Code Compliance with National Fuel Gas Code and design Criteria for NFGC Compliance. Proper system design is examined with pressure drop and draft calculations as well as the results of inadequate draft and over draft control. Finally, proper application of design is reviewed as it pertains to high efficiency, condensing hydronic heating systems.