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Mian vent / Hot Water Zone on Steam Boiler

Good afternoon all.  I have a couple of questions that I am in need of assistance on. Before asking, you might need to know the following:  We moved into our home and had an old/oversized Burnham unit replaced with a newer and properly sized WM unit. Everything appears to be in good working order. My only concern after reading some of the info here is that the boiler was piped in copper, but I heard it's not ideal...but also not the end of the world.  We have a one-pipe steam system for a rather small home (5 rads on main floor, 1 rad upstairs in a tradiditonal cape.)

First Question: Right now I have 1 main vent right at the end of the main pipe. It's a "Ventor No.45". After reading some information here, would it be best to replace it with a better vent (like the Gorton ones mentioned here)? I know you need to measure the main, but don;t know exactly what to measure (ALL the piping or just that square main that goes around my basement and feeds the other lines that go to the rads?)

Second Question: There was a hot water loop on the old boiler. It worked ok except when the boiler was making steam, the hot water loop sounded like a freight train!  That sound is still there with the new boiler, but not as bad. I just turn the thermostat down until the boiler shuts down...and then I'm good. Manual, but a pain that should probably be fixed.  Finally (and this only w/ the NEW boiler) even when the circulator pump isn't running, the water in the hot water loop gets hot. It get's hot enough where it warms the whole basement up! (Not sure how this is even possible...but it happens!). To stop it, I've just closed tha ball valves half way to calm the heat down...but then I can't run the circulator pump.

Thanks in advance for any ideas or assistance. Thanks again. Brian


  • Jamie Hall
    Jamie Hall Member Posts: 21,514
    Well now

    the question with the vent is, is it working well enough?  The way to tell is do the various radiators all get steam more or less together?  That is, in a house that size, within a few minutes of each other?  And does the end of the main with the vent get nice and steam hot?  If so, I'd leave it be -- but then, I'm well known on the Wall for "If it ain't broke, don't fix it".  Ditto with the copper -- although I'd make sure it was well insulated, if it isn't.  No, it isn't ideal and yes, it can break the solder joints from expansion and leak.  But again... "If it..."

    I have no idea on the noise in the hot water loop... somebody else will!  As to heating the basement, it's well to remember that the dead men did some fine work with gravity hot water systems, too -- which is what you have.  Again, insulation...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Steve_210
    Steve_210 Member Posts: 628

    do you have a thermoeter on the HW loop if so whatis it reading
  • Steamhead
    Steamhead Member Posts: 16,230
    Still have some work to do here

    first the main vents: Measure the steam pipe from where it leaves the boiler's header to the end where the vent is. Also measure its diameter (outside diameter is fine). I'm positive that #45 is way too small- it was made for use on a convector.

    The hot-water loop circulator should pump away from the boiler, and it needs a bypass between the return side of the loop and the circulator's inlet. The latter is to keep the water from getting so hot that the circulator starts to cavitate, and the former keeps the water in the loop from flashing to steam. Both situations can make lots of noise.

    The loop also needs a flow-check to keep the water from circulating when the pump is off, and an aquastat to stop the burner at about 180 degrees when only the loop (but not the steam) is calling for heat. And the circulator itself should be a bronze 3-piece type that uses oil rather than system water for lubrication. Condensate doesn't lubricate well so a wet-rotor circ won't last long.

    Here are some pics of a steamer with HW loop we installed last year.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • brian_44
    brian_44 Member Posts: 59
    More info...

    Thanks to all who have given info and feedback. It's much appreciated!

    In regard to the question around the radiators heating up together...for the most part yes (except for a behemoth sized (over 4 feet!) radiator some idiot put in our living room. It takes a while to heat across not to mention it's "gurgling" which leads me to believe it's sagging in the middle as it is pitched correctly...) Anyway, all radiators heat up...but it takes about 50-60 minutes after the boiler fires up for them to get fairly hot. I'm thinking that's a long time...

    Steamhead, For the venting question-The piping from the header to the vent is about 45 feet. The outside diameter of the pipe is around 8.5 inches. 

    For the HW loop- I don't see any bypass. The line goes right from the boiler...passes a ball valve and the the pump (about 6 feet from the boiler).FYI, the pump is a B&G NRF-22. I don't see any evidence of a flow check or aquastat (not that I know what they look like).  How hard is it to add those items?
  • Steamhead
    Steamhead Member Posts: 16,230
    edited October 2009
    I think you measured

    the circumference instead of the diameter. The outside diameter (side to side or top to bottom) is probably 2-1/4" or so, which would be a 2" pipe.

    Vent it with a Gorton #2 vent.

    Adding the needed components to the loop is not hard for a knowledgeable pro. Try the Find a Professional page of this site. BTW, the circulator is wrong too.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • Pipe Sizing Chart

    Here's a handy little chart for figuring out pipe size.
  • brian_44
    brian_44 Member Posts: 59

    Thanks much to all.  I will get those items on the loop looked at.  I will also order the Gorton #2 main vent and install asap. (Looks like the best price in on the pexsupply site).

    I'll also get that loop corrected so it's right...after that I should be all set.

    Thanks again,

This discussion has been closed.