should the end of a steam main be insulated?

Bigpickle18

I have 2 inch fiberglass insulation that starts from the riser all the way to the last branch on the main. the last 2-3.5 feet is uninsulated. I’ve done some reading and asked around and was told the end portion of the main should be left uninsulated because that’s where the steam needs to turn to water to return to the boiler, and to avoid having spitting main vents.

is any of this accurate? should they be insulated or left bare?

109A_5

Hello Bigpickle18,

Although it probably does not make much difference I would insulate it unless you like (or need) the heat that is given off in that area. if you don't need the heat there leaving it uninsulated just needlessly makes more condensate. The radiators should be the place where the condensate is made. If the vent at the end of the main is properly placed and the system pressure is correct it should not be spitting water and the main vent should close when the steam gets to it anyways.

Mine is insulated and I have no motivation to change it.