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Steam radiators not heating up

jmora
jmora Member Posts: 13
Hello. I have a Weil McLain steam boiler that has a dry return. My steam radiators seem to have a mind of their own when it comes to getting g steam out if them. I have checked the site glass and it is at 1/4 to 1/3 full. Some of my radiators are hot but only the top halves even though I have new Hoffman vents installed. Some radiators do not get hot only warm but sometimes they stay cold. I have even removed the vents on these when they are cold and no steam comes out. I have removed the service valve tops and cleaned them out and no steam comes out. I do at times get steam at these intermittently. I checked the radiators for water and have drained about 3/4 of a cup. I made sure they are not plugged up. My 2 risers out of the boiler are set to about 3 feet above the boiler, water from the drains comes out clean. The pressure gage seems not to move but its always been like that. All the radiators and the main pipes that I can see in the basement are pitched to drain. Anyone have any ideas? Thank you

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 20,462
    A dry return? And vents on the radiators? And single pipe radiators? Does not compute.

    That said, as you have surmised, if a radiator isn't getting any steam, something -- most likely a poorly pitched pipe somewhere -- is blocking the steam, but possibly an incorrect steam main routing. Do you have vents on the mains? And how are they configured? You note you have two risers. By that do you mean two pipes coming up from the boiler feeding a header, which in turn feeds the steam mains? Do the mains go out and stop, with a main vent?

    Could you draw a sketch of the layout of the system, showing the relative location of the steam mains, the "dry returns" (I wonder what they really are...) and the vents and the problem radiators?
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 13,136
    Will need pictures of the boiler and a couple of radiators to diagnose. Stand back from the boiler and take pictures of all the piping around the boiler.

    And keep the gauge glass half full, possibly your cutting out on low water.

    Also watch the gauge glass when the boiler is on and steaming. Does the water in the gauge glass bounce a lot like more than an inch or so?

    That's enough to get started
  • jmora
    jmora Member Posts: 13

  • jmora
    jmora Member Posts: 13
    As requested, I posted a picture of one radiator, the boiler with dusl header pipes, the dry return that has a Hoffman vertical vent valve. I do not see any other vents in my basement, I also posted pix of one of the main pipes which is very hot when the boiler is on, all pitched, the other main pipe is hidden in the ceiling but the one small area that is visible, I can fell it very hot. The cut in is now set to .3 and cut out is +1 as per what I read. The cut in prior was set to 3 and cut out at +2, I adjusted it and didn't make a difference. Thank you
  • neilc
    neilc Member Posts: 2,087
    the radiator picture,
    post a picture of the other end showing the vent,
    I think I see it laying sideways there, wouldn't work well like that
    known to beat dead horses
  • jmora
    jmora Member Posts: 13

  • jmora
    jmora Member Posts: 13
    Definitely wouldn't work sideways  :)
  • neilc
    neilc Member Posts: 2,087
    that other picture sure looks like the top of a bullet laying to the left,
    hard to debate this picture,

    do those risers connect above? or just turn into your mains?
    even if they do, your equalizer off the side of the first isn't doing you any good for drying steam,
    you kinda have a coffee perculator there throwing wet steam up and about the house,
    not sure why it works ok some time, and not others,
    maybe longer run times when it's colder ???
    known to beat dead horses
  • jmora
    jmora Member Posts: 13
    The 2 riser manifold pipes which are at least 2 feet above the boiler top as per the mfg suggestion, just turn into mains and are not connected to each other. This boiler worked well for about 25 years until about a month ago. The bubble in the level is to the left since the radiator is higher on the left side so it can drain back to the single pipe. The heat does perform better if the starting temp is low and you raise it about 5 degrees but still have some rads that do not get hot. Thank you.
  • jmora
    jmora Member Posts: 13
    Uploading another picture showing both manifolds. Today I put a vacuum where I removed the hoffman vent and checked that each radiator had flow. I also checked from the return vent to the boiler safety valve and that had good flow. I'm thinking that maybe a crossover pipe should go across the manifolds, any thoughts? Thank you. 
  • neilc
    neilc Member Posts: 2,087
    edited January 2021
    well that dual riser / main assembly is, different,
    but you say it has worked for the last many years,
    so, what has changed?
    makes me think pressure, or venting,
    if you pull off that gage, can you breath down thru that piping, or pour water, lots of water, back into the boiler?
    it's not clogged up at all?
    would be helpful to add a low pressure gage there to make it easier to detect pressure,
    as the boiler starts firing and making steam, is that main vent, venting?
    known to beat dead horses
  • JUGHNE
    JUGHNE Member Posts: 10,308
    You have 2 mains, do you have 2 dry returns tied together somewhere?
    Can you show us where they tie together? Floor to ceiling pictures.
  • jmora
    jmora Member Posts: 13
    Only one return and the stak with the return seems to be the one with less steam. Nothing has changed, ill pour some water down the pigtail tomorrow to see if it isn't clogged. Today I also closed all the service valves on the working radiators and  turned it on for 2 hrs. The cold ones eventually got warm very slowly and eventually after almost 4 hrs got hot. Except for one small entrance one that's still cold. I'll soon turn the valves back on and see if they remain hot but that one may be the issue. Thanks!
  • Jamie Hall
    Jamie Hall Member Posts: 20,462
    Time to take a deep breath and go back to square one.

    First off: you note that you closed all the service valves on the working radiators and turned on the boiler for 2 hours. The cold radiators eventually got warm... May I ask what happened to the boiler pressure for those 2 hours? You cut your radiator load to less than half. The boiler should have had ample capacity to heat those radiators -- but didn't. If the pressure didn't rise and the boiler cycle on pressure, that steam it was making had to go somewhere. This is a potential problem.

    Related to that -- if the boiler is running and making steam and it isn't getting to the radiators, either it's ound somewhere else to go which is easier -- see first off -- or there is something blocking it from going where it's wanted. So the next project is to see how far it does get towards those radiators. Follow the pipes, and see where they go from warm to cold.

    Third, is there any common factor for the radiators which don't get hot? If so, what?
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Dairon421
    Dairon421 Member Posts: 78
    Ok from what I see from your pictures  is that non of your steam lines are insulated.  When steam lines are not insulated  they lose alot of heat and by time it hit those radiators it won't be as hot. Try turning your thermostat  all the way up to see if all radiators get hot. Also, if your thermostat  is in a room near a radiator, that can throw off the other radiators also because it  will satisfy the thermostat  before all the other radiators  get warm. If that not the case then find the btu of your boiler and do a EDR Rating  to make  sure it sized correctly. 
  • Dairon421
    Dairon421 Member Posts: 78
    Your feed water is to close entering the boiler also. Don't  want to shock the boiler and cause a crack. Changing that will give  your boiler a higher lifespan .
  • neilc
    neilc Member Posts: 2,087
    another thing to check, Saturday morning, while it's frigid,
    Is there a cloud of steam coming from your chimney?
    maybe boiler is leaking out the top,
    are you using much water? filling it alot?

    and back to venting,
    those 2 risers into mains, each of the mains need a main vent,
    you show one, small one,
    are they both there and working?
    known to beat dead horses
  • jmora
    jmora Member Posts: 13
    Hi NeilC. Thanks for taking your valuable time in helping me figure this out. My boiler does not use a lot of water, since I only have to add a bit about every  3 weeks and no steam out the chimney so that isn't the problem. Today I had a friend come over for his opinion, he is the super of a large building with many years of boiler expertise . I showed him how the two manifolds both go out individually to each side of my basement. He stated he never saw a setup like mine with that one small return and the two manifolds. He also stated that I may need to have a steam trap installed.  I visited 2 other neighbors in my area that have a similar boiler as mine and their boiler hookup uses 1 of the manifolds and that one is attached to the two main pipes. Both boilers have wet returns. I'm wondering if I should seal the 2nd manifold and do the same setup but with my dry return. I am going to go see 2 more neighbors boilers tomorrow. These other neighbors have very similar houses as mine and were both converted many years ago from their old oil systems to the current which is like mine. They both told me that some of their radiators stay cold. Not sure yet of their situation.   Thanks
  • neilc
    neilc Member Posts: 2,087
    edited January 2021
    you live in a steam village, cool, where?
    the boiler needs to be repiped, properly,
    (not sealing off that riser you're thinking of)
    download your boiler manual and find the piping diagram to see a proper header and equalizer,
    (riser, riser, main, main, equalizer, in that order, aim for that).
    then there's still the issue of 2 mains and one vent, and without being there, more pictures or a good diagram to figure out what the rest of your basement is doing , , , not sure adding a trap helps or hurts without seeing more.
    here's a book from this sight, you and your neighbors want to read, it's an easy read.
    https://heatinghelp.com/store/detail/we-got-steam-heat-a-homeowners-guide-to-peaceful-coexistence
    https://heatinghelp.com/store/
    and there's this,
    https://heatinghelp.com/find-a-contractor/
    you want a guy from here,
    where are you?
    your neighbors' cold rads issues are venting, or their valves are shut, guessing , , ,
    (#I'm psycotic)
    known to beat dead horses
  • jmora
    jmora Member Posts: 13
    Hi Neilc. I read that short but informative reading. I live in Flushing NY. My home was built in 1936 so I have a feeling that it has the piping issue that was designed for the Coal burners. Most of my pipes are in the ceiling of my basement covered with sheetrock but I have the one main that gets hot faster go around from the boiler them goes around the perimeter of the house till eventually meets up with the second main which ends up going to the second manifold. I can see that they tapped from the second manifold to feed the dry return pipe where the one vent is about 12 feet from the boiler. I looked up a plumber from the link you gave me. I'm going to tackle it a little more before calling one. Could my boiler be built up with rust so that it is inefficient? It is about 20 years old and I always run water out of it till it is clear every month. I'll most likely have a very es to call one of those guys but don't want a guesser which I can do. One neighbor had a plumber in his house a week ago, replaced all the air vents then sold him a new gas valve which he claimed was causing the boiler not to heat es nought because the pilot wasn't hot enough. Thank you
  • neilc
    neilc Member Posts: 2,087
    so the 2 risers out of the boiler make one big loop around the basement,
    I think you're right about the coal burner piping and lazy venting, now you're banging on and off,

    and depending on which riser is feeling stronger , and the moon, and wind , , ,
    you're trapping an air pocket sometimes to the right, sometimes to the left, of whatever venting you have,
    that loop should be split into 2, each ending at a main vent, and then both dropped down to a wet return back to the boiler,
    or,
    maybe your buddy was right about adding that trap, and returning thru dry return(s),
    again, you would want to do both mains, so you don't end up with that nomadic traveling airpocket.

    someone really needs to walk in the basement and if you choose someone from this site you should be in very good hands, I don't think you want your neighbor's gas valve guy,

    the rusty boiler, you could take some water from a low drain, it will be muddy, but they all will be, somewhat, not the issue you're looking for.
    known to beat dead horses
    jmora
  • jmora
    jmora Member Posts: 13
    Btw: I actually don't get banging at all, used to get very light  bangs a while back. I do get air vents at radiators that always get water. What I don't understand is the air pockets. Always thought that steam would go through as long as there was no water. I guess you mean that since there is improper/insufficient venting then the steam can't go through.  Thank you
  • jmora
    jmora Member Posts: 13
    Update. A neighbor who is a mechanic told me that his heating system had a similar issue. Turned out that the screen inside the gas valve had some contaminants.  He cleaned it out and his flame output improved and that resolved his issue. I'm going to look at mine. I see a nice blue flame but perhaps it isn't as good as it should be. 
    Thank you
  • Jamie Hall
    Jamie Hall Member Posts: 20,462
    Keep in mind one thing: this isn't a backyard grille, and you can't judge the quality of combustion accurately by eye. You must use test instruments to get the gas pressure and air supply and draughts correct, even if only to get some decent efficiency out of the thing, never mind the heat output which you are paying for.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    jmora
  • Shane_2
    Shane_2 Member Posts: 180
    Check those undersized returns. I had a customer not long ago where half the house wouldn't heat.
    Turns out the 1 inch copper returns for that part of the house were filled with sludge. The steam wouldn't get to the radiators in that area. Cleaned those returns and everything went back to normal.

    When the time comes for a new boiler, get someone in to replace all the returns and fix the near boiler piping.
    jmora
  • jmora
    jmora Member Posts: 13
    Found the problem. Replaced gas valve with a Honeywell Y8610U electronic ignition retrofit and boiler is back to normal. I looked at the old gas valve and found that the screen on the outlet side was clogged about 80% or more. Why to plumbers mount valves vertically so that dust from pipes clog the screens? I gather job security.