ASME stands for The American Society of Mechanical Engineers. This organization has standards for design, materials, construction, and testing of many different things including the pressure vessels of boilers.
Some states, including Massachusetts, Michigan, Oregon and others require ASME certification for any boiler that’s installed pressurized. Other states require ASME only for commercial installations or for installations above a certain size.
Although it’s possible to install a boiler unpressurized and connect it to the pressurized portion of a heating system by using a heat exchanger, this is not recommended. Any part of a heating system that is unpressurized will be exposed to the atmosphere. Oxygen in the atmosphere will be absorbed by the system water and corrode metal parts, including the steel pressure vessel, cast iron components such as circulators, and other items such as tubing, check valves and “air eliminators”. Using a heat exchanger also adds cost and reduces efficiency.
For any application that requires ASME, our EcoBoiler or any one of the EvoTherm boilers (except the smallest) will satisfy the requirements. For an ASME boiler, look for the “H-stamp” in the product literature. The H-stamp will also be included on the label affixed to the boiler jacket.
