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Air Vents

I'm back to my little one-pipe steam house in Meeker Colorado and have jumped onto the learning curve once again. Got a few questions and I'll send 'em out one at a time.

House is about 2500 sf. Built (remodeled, actually) in 1938. Nine radiators in fairly good shape, all above the basement. Main (1) was uninsulated but I've got that 90% taken care of. We were away from the house all spring, summer, fall and into early January. The boiler fired down on low water at some point. (Caused me no end of problems that I won't go into). Re-occupied the house, re-filled the boiler, fired the system.

Noisy! I get the small amount of popping that goes on and fully expect it to go away when I finish insulating the pipes (at least the ones I can access). But the air vents vent on and on and on and on and eventually weep steam as well as air. They whistle and hiss and drive my wife crazy. These vents are all identical. They say Hoffman "Airport" #7. They look to be the original vents. Local supply house says they have replacement vents for $37 each. I read Dan's scoop on Air Vents but I'm cheap so I've got 'em soaking (a few at a time) in vinegar to try to clean 'em up. Oh, and by the way, in 4 days at the house recently, I lost about a gallon of water from the boiler (3" on the sight glass). There's no signs of leaks (other than the vents and obvious floor damage under several sections of a few of the radiators, which I take to indicate that historically wet steam has gotten up there along with elevated pressure.)

Here's what I'm wondering: What's with the "#7" on the vent? Most of you guys are at sea level and so's your experience. I'm at 6,300 feet and so are the vents. The vents operate on temperature differential. At sea level your steam is 212 degrees, right? At 6,300 feet my steam is only about 198 degrees (?). Does that mean that my vents don't want to close all the way when steam gets to 'em? Or is that where the "#7" comes in? Did Hoffman make high altitude vents for the Rocky Mountains? Is this an issue for me or am I picking nits? The supply house guy says he never heard of this issue, that he has 236 #40 vents in stock take 'em or leave 'em.

So there it is. I'll let you guys weigh in now. I'm just a confused soul.



    JUGHNE Member Posts: 11,060
    It is a pressurized system, it doesn't know if it on Mt Everest or in Boston.

    That is why pressure cookers are used where you are.
  • neilc
    neilc Member Posts: 2,703
    whistle and hiss, noisey vents, could be a matter of too high a pressure at the boiler,
    what are you set for, and what are you seeing on the gage?
    post picture of your Pressuretrol, sight gage,
    and a general distant shot of the boiler, floor to ceiling, including the piping above the boiler,
    what do you have for main vents? picture there also,
    known to beat dead horses
  • neilc
    neilc Member Posts: 2,703
    you also mention loosing water,
    is there a plume coming from the chimney?
    known to beat dead horses
  • ccstelmo
    ccstelmo Member Posts: 31
    Hey, thanks, neilc. I'll be getting back over to Meeker later this week and will send the pictures.

    Jughne: I'm thinking it's not a pressurized system until (and unless) all those vents are closed?
  • ChrisJ
    ChrisJ Member Posts: 15,667
    ccstelmo said:

    Hey, thanks, neilc. I'll be getting back over to Meeker later this week and will send the pictures.

    Jughne: I'm thinking it's not a pressurized system until (and unless) all those vents are closed?

    I'm kinda leaning towards agreeing with you.
    My system runs just over atmosphere so I'd hardly consider it a pressurized system.

    But, I also think my Gorton vents close quite a bit below 190F. Not sure about Hoffmans with the alcohol mixture in the "oil caning" capsule.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment