Steam vent size depends on the radiator's BTU output and how quickly it needs to release air. Vent speed is typically marked on the vent itself (e.g. #4, #5, #6), and checking the radiator's rating helps confirm the right size. See the BTU calculator. The size of the orifice required depends on the distance the vent is from the boiler or in the steam line. The closer the vent to the boiler, the smaller the orifice required. See the helpful rating chart.
Bronx, NY 10474
