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Hammering from radiator

I have a radiator making water hammering sounds. The supply valve is open all the way and the radiator is pitched down to the pipe. It has a Varivalve Quick Vent.

 It hammers with the vent open different amounts and when it's closed. When it's closed, more time passes from when the boiler goes on to when the sound starts.

There are sometimes little drips of water or sputtering from the vent.

From what I've read on this forum, these vents aren't ideal. Would replacing it with something else fix the hammering? Or could the supply valve be broken and not actually all the way open?

The boiler is Weil McLain a/b-368. It's one-pipe steam.


Thanks for any suggestions.

Comments

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,455
    The way it's piped it should work as there is no horizontal pipe to be pitched wrong. It could be a problem inside the valve. I would try a new vent, but I doubt that will fix it.

    How is the water level in the boiler when it is steaming? Is it steady bouncing an inch or less? Or is it bouncing more than that? Do you have any main vents? Is this the only radiator you are having problems with? Are you running the pressure at 1.5 psi or less?
  • neilc
    neilc Member Posts: 2,692
    you could try taking the vent off, and plugging the vent hole,
    it shouldn't heat, much,
    but if it goes silent for hammering then you know it's the venting issue

    or try a different vent,

    and as Ed asks,
    what pressure are you seeing on the gage?
    and has the pigtail and trapped pipe been serviced?

    I feel any device or gage should be above the trap of the pigtail.
    or the devices are sitting in water and glop
    known to beat dead horses
  • ilikebeans
    ilikebeans Member Posts: 18
    The way it's piped it should work as there is no horizontal pipe to be pitched wrong. It could be a problem inside the valve. I would try a new vent, but I doubt that will fix it. How is the water level in the boiler when it is steaming? Is it steady bouncing an inch or less? Or is it bouncing more than that? Do you have any main vents? Is this the only radiator you are having problems with? Are you running the pressure at 1.5 psi or less?
    The water level bounces frequently, but it stays within roughly one inch.

    The only vent I see is this:


    Ventrite 33
    I don't hear any sound like hissing or clicking from this vent.
    This is the psi setting(?):

    On the gauge it reaches 5 psi, then the boiler shuts off. It starts again after about 2 minutes when the gauge shows around 3 psi.

    From the start the pressure stays at 2 psi for 40 minutes, then within another 10 mins it goes up to 5psi. The hammering sound in the problem radiator starts after about 30 minutes from the start with the vent closed all the way. It's a constant rapid hammering sound.

    The other radiators don't have any issues.



  • jhewings
    jhewings Member Posts: 139
    edited April 2022
    5 psi is way too high. If your gauge is accurate then the pressuretrol is not working properly. Has the pipe below it been cleaned? If not, you should clean it all the way to the boiler (and add water back in the pipe so steam doesn't reach the pressuretrol and gauge) . It looks like it should be shutting down the boiler at about 1.5 psi which would be about right. The pressure should never exceed 2 psi. Most of us here with steam heat have added 0-3 or a 0-5 psi gauge because the 0-30 is not very useful. You still need to keep the 0-30 gauge for code. I suggest you try to get your pressuretrol working first by cleaning the pipe below it. But you will not know how well it is working without a 0-3 or 0-5 gauge.
    You will have to find out why your pressure goes so high. The reason could be poor venting. You probably need a new main vent such as a Gorton #2 and a new vent for that radiator.
    ethicalpaul
  • pedmec
    pedmec Member Posts: 959
    sounds like you have a broken radiator valve. the disc breaks of the stem and just kind of sits on the inlet of the valve body reducing the area for steam and condensate to pass each other. steam throws the condensate back toward the air vent. one pipe steam. valves is either all the way open or completely closed.
  • ilikebeans
    ilikebeans Member Posts: 18
    edited May 2022
    I talked to the guy from the oil company who does the yearly maintenance on the boiler. He didn't agree with the idea of venting the main because there are already vents on the radiators and putting a vent on the main would interfere somehow. Any thoughts on this?

    As for the ventrite 33, he said it's just there to "break vacuum," so it isn't a problem if there's no sound of air escaping from it.

    But we did agree that the service valve for the noisy radiator probably needs to be replaced to fix the hammering sound and that something is not working with the pressuretrol or psi gauge.
  • Jamie Hall
    Jamie Hall Member Posts: 23,170
    The guy from the oil company clearly doesn't understand how venting works. That poor little Ventrite on the main is woefully undersized.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • ethicalpaul
    ethicalpaul Member Posts: 5,695
    edited May 2022
    Another great reason to convert to natural gas. I never had someone from the gas company come to my house and charge me to tell me 100% incorrect info about my boiler
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
  • ilikebeans
    ilikebeans Member Posts: 18
    Turns out the valve was completely broken off inside.


  • pecmsg
    pecmsg Member Posts: 4,776

    Turns out the valve was completely broken off inside.


    that will do it.

    Good find!
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,725

    Another great reason to convert to natural gas. I never had someone from the gas company come to my house and charge me to tell me 100% incorrect info about my boiler

    That's not fair Paul.

    If I worked for the gas company or the oil company (if you had OilHeat), and came into your home and saw your boiler, I would keep my mouth shut and listen. By the looks of your system YOU KNOW MORE about steam heat than 95% of the regular technicians out there.

    No one could tell you anything you don't already know about your own system. And I love your videos!

    The average home owner has no reference point and many times fall short because of misinformation from "The Oil Company" or even "The Gas Company"

    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    ethicalpaul
  • ethicalpaul
    ethicalpaul Member Posts: 5,695
    edited June 2022
    Life's not fair, Ed :smile:

    Regardless of my particular situation I stand by my advice. Gas just requires less maintenance, that is indisputable. There are way more technicians out there who can keep an atmospheric burner running well than there are technicians who can keep an oil burner running well (correct me if I'm wrong).

    Because of the increased maintenance, and the commonness of "won't start" problems, oil pretty much requires an annual service contract or expensive non-contract visits, usually during holiday weekends :sweat_smile:

    You don't know who you're going to get when this occurs. Is it going to be someone who knows what they are doing, or is it going to be a guy who tells you that main venting is unnecessary, as happened in this thread? Roll the dice and find out!

    With a little knowledge from this site, any homeowner can perform the super easy annual service required by an atmospheric gas boiler. But even I, who is unafraid and willing to do a lot of learning, am unable to properly clean and adjust an oil burner. It's too difficult, dirty, and requires expensive measuring tools. As we all know, it's even too difficult for many oil contractors to do correctly (!!!!)

    So for all those reasons (and more unmentioned here) I will always advise fellow homeowners to convert to gas if they can.

    Thanks for the kind words about my videos, I have another one in the can to release whenever I can get to it about Surge-X :smile:
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el