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Capping unused steam pipe in 1 pipe steam sysytem
Just finished a big renovation, part of that was taking down some walls on our first floor. There was an old steam pipe which lead to the upstairs bathroom. The upstairs bathroom however does not have steam heat radiator (was removed by previous owner) the pipe never got hot, so assumed it was dead. it was removed, and the work finished. yesterday needed to turn the heat on for the first time, and went to check the boiler to find steam shooting through the old pipe, it had not been capped. Plumber came, cut the line and capped it. My question is, why would steam still be shooting through this pipe, weird since it never got hot, and then is capping it ok to do?