The Vent-Rite 3575 or 77 are intended for main vents two pipe systems and located on the mains. Jump to Latest Follow 1 - 5 of 5 Posts. How Steam Radiator Air Vents Work Steam Radiators Steam Boiler Steam Valve So the total amount of air we have to vent is 52 cubic feet plus 28 cubic feet which gives us a total of 80 cubic feet. Steam radiator vent sizes . Inverted bucket traps are selected based on size and pressure rating which can range from 0 to 2500 psig. NPT angle connection Single non-adjustable port Maximum operating pressure 6 psi for ordinary one-pipe system that doesnt require proportional venting Steam Air Vent. IPS Angled Steam Radiator Vent Valve is made for a steam heating system. Tankless Water Heater Connection Valves. A vent port size for every room from the largest size for the coldest rooms to the smallest size for the too hot rooms. Earls LS Steam Vent ADPT One -3 SGL One -3 Dual Out. This Is A Great Replacement For Old Rusty Or Leaky Radiator...