Freddy wrote:The difference is ASME rating. Commercial applications it is often demanded by the state or the insurance companies. The AHS get's an extra $2,000 for basically the same boiler if you want the ASME sticker. Basically it is a paperwork trail of the steel and parts in the boiler as well as documentation of who welded it and their certification.
It also includes inspections by ASME certified inspectors of the internal welds, materials and manufacturing processes. You are looking for an H stamped boiler.