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Radiator Air Vents loud hissing

AMMY
AMMY Member Posts: 7
I have a 100 year old house in NY that has a Burnham boiler and 6 radiators. All the rads hive a loud hiss when heating up. They all have Gordon air vents (#4,5, 6, or C). It has a 
Honeywell PA404A1033 pressuretrol, but it never trips and the pressure gauge doesn't move. 
Could the hissing be due to high pressure in the boiler moving the air too fast? 

New to boilers so any help is appreciated. 

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 17,049
    Could well be too high a pressure -- hissing vents often do that. Which, in turn, may indicate that the little pipe from the boiler to the pressuretrol is plugged. That often happens. What is the pressuretrol set at?
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • jhewings
    jhewings Member Posts: 33
    Do you know if you have good main vents in the basement? They are on the steam mains, often but not always near the boiler. Main vents are important and if they are absent or not working then their job ends up in the radiator vents, which are not big enough or intended to vent the mains.
    wlgann
  • AMMY
    AMMY Member Posts: 7
    The pressuretrol is set at 1.5psi. Differential is at 1 and then 0.5psi on the the front display. The pigtail is less than a year old as it was replaced with a brass one last winter. 

    I am not sure if there are main vents as the basement was finished by the previous owners. There is a section of the basement ceiling with tin ceiling tiles so I'll take a look under that area to see if there are main vents.

    Thanks!


  • wlgann
    wlgann Member Posts: 9
    Main venting is a legit concern. But before you tear out your ceiling:
    1. Make sure that each radiator has a small slope toward the valve end. One eighth inch per foot of slope is enough. Because if condensate backs up in the bottom of the radiator it can get blown up toward the vent by the incoming steam.
    2. Try switching for smaller vents on the radiators. Try one size down, or even two sizes if you have a room that's overheated. Since you seem to have a variety you can maybe swap a couple and see if you can get a smaller valve on at least one radiator, and if that one quiets down you know what to do. Condensate dripping down from the radiator needs to bypass the incoming steam in the same pipe. A smaller vent on the radiator will slow down the incoming steam and keep it from blowing the condensate back up into the radiator.
    3. Last, hardest-to-fix yet least likely potential trouble spot is any horizontal run of pipe between the main and the radiator. If that's not sloped correctly (say, due to the building having settled), then condensate will back up in that pipe and get blown back up into the radiator.
  • AMMY
    AMMY Member Posts: 7
    Wlgann,

    All rads a pitched. No condensate coming from the air vents.
    However, your suggestion on the air vent number is worth the try. The rads upstairs all have Gorton No C (12 section and 22 section). Rads on 1st flour are 4 and 5 ( both 22 section rads). 

    Should I try a better air vent instead Gordon's? Any suggestions on which one?
  • wlgann
    wlgann Member Posts: 9
    AMMY said:

    The rads upstairs all have Gorton No C (12 section and 22 section). Rads on 1st flour are 4 and 5 ( both 22 section rads). 

    Should I try a better air vent instead Gordon's? Any suggestions on which one?

    Interesting the C-size is on both a little and large radiator. And they both hiss like crazy? I would've expected a #5 or even a #6 on the 12 section radiator unless it's 6 feet tall or at the end of 90 feet of pipe.

    I like the Gorton vents just fine and have several in my house. If you needed to replace any of them I would replace with Maid o' Mist because they come with a half dozen different apertures that you can screw onto the vent by hand, for only a few bucks more than the single-size Gortons.
  • neilc
    neilc Member Posts: 1,461
    AMMY said:

    Honeywell PA404A1033 pressuretrol, but it never trips and the pressure gauge doesn't move.

    I know you said new brass last year,
    it could still be not working / clogged somewhere there,
    can we see pictures of the pigtail and Ptrol, where they're connected,
    and the gage also,
    can you easily blow thru the pigtail back into the boiler?
  • AMMY
    AMMY Member Posts: 7
    So today I tested the pressuretrol by manually triggering it and it did shut down the boiler. So, I know it's working. Next, I removed the pressuretrol and pigtail and the pigtail was clear. 
    Still need to check if I have any vents on the main. Also, whether my air vents on the rads are the correct size. Two of the largest rads (22 sections each) are on the first floor and the affect the thermostat. They may have vents that are too large.
    Still trying to figure this out.

    Thanks for all the advice!

  • neilc
    neilc Member Posts: 1,461
    at the risk of beating dead horses,
    did you remove the pigtail and blow thru it, or did you blow thru the pigtail as it is mounted on the boiler?
    cuz the 90, and that port into the boiler could be jambed also,
    too high pressure can cause vents to cry, wet steam also,

    that boiler is not piped to spec, and is sending wetter than need be steam up and about,
    do you have your manual?
    was the boiler installed prior to you buying the house? or can you get your installer back?

    consider mounting a low pressure gage, 0-3, 0-5, 0-15, what ever, with the Ptrol,
    those 0-30s can be inaccurate, hard to read, and subject to failure or plugging themselves mounted down there,
  • AMMY
    AMMY Member Posts: 7
    I took the pigtail completely off and blew through it. The 90 was clear, but I didn't take it of to check the horizontal it's attached to so that could be clogged.
    I bought the house in February of this year and the boiler was already here. I had a winter maintenance done by a reputable plumbing company but there was no mention of it being installed incorrectly. What in the image tells you it is not to spec and sending wet steam? I'm asking for knowledge, not a challenge. I'm more familiar with forced air furnace. Boilers are new for me.

    Where can I find a 0-3 or 0-5 guage. All I ever see is 0-30 or 0-20?
    I believe the manual as is still taped to the side of the boiler. What should I look for in the manual?

    Thanks 


  • neilc
    neilc Member Posts: 1,461
    edited November 20
    check the small hole inside the female thread to the Ptrol also, it's not likely, but a could be,

    if you have your manual there will be a page or 2 showing the near boiler piping,
    full size up and out as your's is, but then 90 horizontal with swing joint(s), as that smaller pipe does, but still full size or larger(manual spec), and then 90 down where that low pipe returns the the boiler(your equalizer),
    the horizontal stretch is referred to as the Header,
    the 2 house mains get piped down the the header,
    if there are 2 or more risers from the boiler, pipe sequence across the header would be,
    boiler riser(s), then the system main(s), then the equalizer,

    it's in that manual,
    post a pic of the other side where the return joins back to the boiler,
  • Jamie Hall
    Jamie Hall Member Posts: 17,049
    The main thing wrong with your boiler's piping is that the riser -- the vertical pipe coming out of the boiler -- goes right on straight up and attaches to one of the steam mains in the house. This means that any water droplets carried out with the rising steam will also keep right on going up and get into that steam main. How much of a problem is this? If the system were completely quiet and no hissing or spitting vents, I'd say it was just an example of how forgiving steam is of incorrect installation. In your case, it may well be part of your hissing problem. Is it worth fixing? Hmm... probably not, but...

    What should happen is that the pipe would come straight up for about two feet, and then turn horizontal -- the same size or, ideally, one size larger to a pipe called the header. It would then go horizontally (well, actually with a slight downward slope away from the riser) over to the pipe which goes down in back of the boiler, called the equalizer. The two steam mains which I see would come down to that header and be tapped independently off the top of the header. What happens in that arrangement is that those water droplets would get into the header, but tend to fall towards the bottom of it and be carried over to the equalizer and go back to the boiler, while much cleaner steam would go out the two steam main connections.

    0 to 3 or 0 to 5 psi gauges can be found on Amazon. Not aerospace quality, but plenty good for what we do.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • AMMY
    AMMY Member Posts: 7
    New York City...
    Thanks for all the help and knowledge. I've got to get this figured out. 
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 10,268
    edited November 21
    @AMMY

    @JohnNY is you guy you can pm him
  • AMMY
    AMMY Member Posts: 7
    Ok. I'll give him a shout.

    I'm sure the forum will here from me again.

    Thanks!