A steam boiler that runs at or below 15 psi (or psig) is a low-pressure boiler. The ASME calls this a "heating boiler". Minnesota calls it low-pressure.
A steam boiler running above 15 psi is a high-pressure boiler. The ASME calls these "power boilers". Minnesota calls them high-pressure boilers.
A hot water (hydronic) boiler that runs at or below BOTH of the following is a low-pressure boiler:
250 degrees Fahrenheit -AND-
160 psi (or psig)
A hot water (hydronic) boiler that runs above either of the above numbers is a high-pressure boiler. These are sometimes called "high-pressure, high-temperature" boilers.
-Reed |