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how would efficiency of steam boiler be,if additional venting is put in place on mains - single line

LS123 Member Posts: 456
I have a considerably efficient steam heat system. there are two gorton #1 on two mains in the basement. They work fine and satisfied with the product. I was wondering If I were to add two more gorton #1 vents to each main in the basement (steam pipe are insulated) basement is also considerably air tight.
would having extra set of air vents on the mains increase performance? Would that hinder current efficiency and performance?
Thank you!
Thank you!


  • Jamie Hall
    Jamie Hall Member Posts: 18,951
    There are two aspects to this, realistically. The first, of course, is the actual efficiency of the boiler -- and additional venting won't change that (well, technically, it might change it by a fraction of a percent if the venting were really really bad and the pressure went sky high, but... !). The other, however, could be significant. That aspect is how rapidly and evenly does steam get from the boiler to the radiation, which is where it's useful. And again there are two aspects to this: the evenness of distribution, which in a one pipe system is more a matter of the radiator vents, and the other is how well air gets out of the mains.

    OK. Prologue over. By FAR the best way to determine if you have adequate main venting is to put a low pressure gauge on the boiler (on the header is the best, but that usually involves tapping the header for a new pigtail and other complications, show just putting it on the same pigtail as your pressure control will do) and the observing that gauge as the boiler fires from cold. If the main venting is adequate, what you will observe is that the pressure will rise to a fraction of an ounce to a few ounces almost as soon as steam starts to form -- and then it will stay there, almost constant, until all or most of the radiator vents are closed.

    In terms of heat efficiency -- converting fuel into comfort -- the difference between adequate and inadequate venting is small, but may be noticeable -- perhaps a few percent if the boiler cuts off on pressure before the radiation is mostly full.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • LS123
    LS123 Member Posts: 456
    @Jamie Hall , thank you. Currently there is a 30 PSI in the front of the boiler, 3 PSI connected to a pig tail and Ptrol. Even during the most coldest days low PSI gauge would not go above 0.5 PSI. Back of the house heaters much closer to the main, steam get to the rads always faster than the front of the house rads (and always second floor rads get heated first as expected). Since the basement and main pipes are insulated, it takes far less time to get the rads hot. Perhaps adding one more adequately sized main vent for the main going to the front of the house, probably increase the heating time in the front of the house rads in my case. Thank you again!
    Thank you!