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Steam coming from new vents

AlexR Member Posts: 61
I installed new vents on my mains and radiators today, all Gortons.  I noticed steam coming from both main vents (#2s) and one of the radiators after they were hot to the touch.  The advice here for steaming vents seems to be to boil in vinegar- does that go for new vents too?  Is it plausible that a functional new vent might need washing, or should I suspect something else (bad vent, pressure too high, etc)?


  • Vents

    While you can get a bad new vent, I'd also check for something else. At what pressure are you running your system? It shouldn't be more than 2 PSI and preferably lower than that.

    Also in the future I would only change one item at a time and make sure that's running okay before changing something else. That way you'll be able to easily pinpoint if a particular`item isn't working. If you change multiple items it can be hard to tell which one is having the problem.

    - Rod
  • AlexR
    AlexR Member Posts: 61
    edited November 2009
    supposedly 1.5psi

    The pressuretrol is set for about 1.5psi cutout (~.5 cut in).  But it's a L404F, so the scale's only marked from 1-8psi and I don't know how much lower I can turn it down.  I don't have a low pressure gauge yet (that's next).  The 0-30psi gauge reads between 2 and 3psi, so I don't think I'm running over 3 or 4, but it may well be above 2.
  • Jamie Hall
    Jamie Hall Member Posts: 19,968

    your 0 - 30 gauge is even reading, never mind reading 2 to 3 psi, your pressure is too high.  You will need a vapourstat, almost certainly, to control it where you need it.

    The Gortons can probably take the pressure, but the sooner you get it down the happier both you and they are going to be...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • AlexR
    AlexR Member Posts: 61
    pigtail question

    My low pressure gauge, brass pigtail, and other fittings showed up today.  The plan is to replace the iron pigtail, put a tee on top, and then the pressuretrol and gauge (I saw the vaporstat recommendation, but I'm working with what I have on hand...)  I saw some reference to putting water in the pigtail.  Is that right?  Do you just fill the bottom part of the loop?
  • Water in Pigtail

    Don't worry about it, enough water will find its way there on its own.
  • AlexR
    AlexR Member Posts: 61
    low pressure gauge, new pigtail

    I installed the low pressure gauge on a tee with the pressuretrol on top of a new brass pigtail.  The old one has a lot of gunk in it (which was surprising, because the boiler was installed about 2 years ago), so I'm sure that wasn't helping anything. 

    When the boiler runs now, the high pressure gauge goes up to 2 or 3 psi pretty quickly while the low pressure gauge hangs out around .1 psi for a while.  Shortly after all the radiators were hot all the way across, the LPG started increasing.  The pressuretrol cut out when the LPG read about 1.6 and the HPG was still at 3 (the pressuretrol was set for 1, but I understand it's not going to be accurate that low).  There was some steam coming out of the main vents just before the cutout, but much less than the other day.  So a vaporstat is definitely the next step.

    Question 1: assuming the LPG is reading correctly, is it normal for bits of steam to be coming out of the main vents? 1.6psi is right about the recommended pressure in LAoSH, so it seems odd that the vent wouldn't work properly

    Question 2: Having swapped vents on the radiator that was hissing continuously, it's still hissing and spitting water.  I noticed that both the old and new vent were angled towards the radiator, as if the tapping wasn't straight.  How far off vertical is a problem? (the gorton radiator vents seem to have less than a right angle between the body and the threading to start with)

    And while we're here: a huge thank-you to everyone on the site who answers questions- mine and others'.  It's immensely helpful!
  • Vents

    It sounds as though things are running very well.  The indications on the LP Gauge sound right.  Initially at the start of the steam cycle there won't be much pressure as the vents are venting and then the steam is condensing madly on the cold radiator surfaces. When steam condenses it goes from occupying about 1 cubic foot of space down to 1 cubic inch of space and this produces a lot of vacuum so you won't have much pressure build up till the radiators heat up and the condensing slows. At this point the boiler begins to "catch up" and the pressure will slowly rise until it hits the cutoff point.  Just as a suggestion. You might want to start timing the heat cycles and when steam arrives in different location in the system and how long it takes radiators to heat etc. as this then gives you a basis so you can see if a change you make is really beneficial. It also can give you an indication that something isn't running properly in the system and needs to be addressed.

    Question 1: No, the vent isn't working properly. It may have a piece of rust etc. on the seat. Just take it down and blow through it. Some one else just got a Gorton and it was blocked (you couldn't blow through it). Steamhead suggested rinsing it in a basin of warm water so I'd try that too. The vents are used to having water`in them internally so that won't be a problem.. Are both vents still leaking steam?  If that doesn't seem to fix things I'd call Gorton and arrange for an exchange. i understand they are pretty good people t work with.

    Question 2:  First of all you might want to check that the radiator is sloped towards the inlet pipe and that the valve is fully open. Use a bubble level to be sure there is really slope. I had obvious visual slope on one of my radiators but later found it was sloped the wrong way as the whole floor had settled!.

     ideally a radiator vent will be vertical plane as there is a float inside (most radiator vents) the vent which is supposed to shut off the escape of any water. If the vent is "leaning" the contact of the float with the inside wall of the vent maybe sticking things.

    The "lean" is easily corrected by using a short 1/8 inch pipe nipple and an 1/8 elbow and then attaching the vent to that and orienting every thing so the vent is vertical.

    What brand of vent are you using. Some fast vents like the VariVent are notorious for "spitting". if the vent is adjsutable you might try slowing it don or replacing it with a slower vent.  If you want to get into balancing and venting you might want to get Gerry Gill and Steve Pajek's booklet on venting. It's available as a download on this website.

    - Rod

This discussion has been closed.