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Leaky radiators

Big Ed
Big Ed Member Posts: 1,117
The cone thing with the nut on top is a pressure reducing valve or feedvalve. Water enters the boiler from this point and the regulator maintains enough pressure so the system will fill to it's highest point + a few pounds for safety .If there was not enough pressure you could not bleed the upermost radiator. Bleed means letting the air out of the system so the water can move though the system and transfer heat from the boiler to the radiators ..

To remove a radiator , first shut off the feedvalve and boiler then drain down the system below the radiator that is being removed. You may have to open the radiator air vants or bleeders to allow air into the system to replace the draining water .Don't forget to shut the bleeders once you lowered the water level enough before you move on. There should be two unions on each end of the radiator. Always use two good clean pipe wrenches , one turning the nut and the other countering the torque to prevent further damage . Remove the radiators ..Do what ever you want..

Return the radiators ...Clean the union seats with steelwool and dab a pinch of plumbers grease on the union seat . Tighen up the unions with two wrenches...Not super tight , you will retighen later ..Open the feed valve and lisen for air at the joints , retighen if needed . Then bleed the radiators until you get water. Let it heat up and cooldown then retighten oncemore...


  • Jamie Hall
    Jamie Hall Member Posts: 17,726
    Leaky radiators on vapour steam

    I know. The right thing to do is replace them. But...

    I have a few old steam radiators which leak (no surprise) at the joint between the sections. There are some which can be replaced with new ones, but there are others which are odd shapes that I can't seem to find new (typically either too low, to go under a window, or too tall and narrow and I can't fit a wider one in but need the EDR). I'd contemplate splitting the sections (after taking the holding bolts out!) with a crowbar, but... my luck with prying on cast iron ain't too good.

    Has anyone tried fixing such leaks by taking a good high temperature non-hardening sealant, such as Permatex Form-a-gasket, putting a good bead of it on the Outside of the joint, and backing it with a metal band, such as an outsize radiator clamp? The pressures are so low it's gotta hold... (the boiler safety valve is at 10 psi, but the Vapostat is at 10 ounces) and the stuff can handle the temperatures...

    If you tried something like this and it didn't work, why not? What happened?

    If nobody answers, I'm going to try it -- let you know what happens!

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • George Berkeley
    George Berkeley Member Posts: 40
    One fix

    Reported on the Wall about 2 months ago was success by using J-B Weld which can be purchased at some hardware stores.

    Now I have not tired it, but at least one person did and was happy with the result.
  • Ernie
    Ernie Member Posts: 94
    Leaking radiator sections

    Do you have a phone number contact. I have successfully used anerobic sealants on hot water systems that run at 15-20 psi without leaking. A lot easier to use than J-Weld and does not require mixing 2 components together. These sealants will also with stand 400*F temperatures. Will save you the trouble of trying to take apart radiator sections.
  • Steamhead
    Steamhead Member Posts: 15,025
    If that doesn't work

    you can get new push-nipples made- these are most likely the parts that are leaking. Contact Oneida County Boiler Works at (315)732-7914. You'll have to send them a sample they can use as a pattern.

    You also need to determine why they failed. Most likely you have an acid condensate problem, which believe it or not results from poor air venting. How does the air get out of this system?

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    All Steamed Up, Inc.
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  • Big Ed
    Big Ed Member Posts: 1,117

    Yes , years ago we had to split the boilers so we can bring them down the basement stairs and we reassemabled the boiler back in the basement with permatex . (A normal install was also three day work)...Can't remember if it were soft set or hard. Anyway a radiator is built like a boiler. First make sure the radiator is cool and not hot before you split the sections . Then use evenly spaced wedges around the pushnipple to split the sections.If I remember the wedge set was made of metal..We are going back when I was alittle Lad.... If the pushnipples are leaking after all these year I would supect a crack,if not then you need new push nipples ,they could be rotted....In the old days they use Oaka and hemp to help seal pushnipples.......
  • Jamie Hall
    Jamie Hall Member Posts: 17,726
    Thanks, guys!

    I knew I would get some good advice...

    I have one radiator I don't really need... I'll try splitting it and seeing what kind of push nipples there are in there (if there's anything left... 'rotten' may be a kind term...) and see about getting some; I will try some of the other tricks on one or two others.

    The amazing thing is that there are only a few leakers in the whole lot -- and the thing hasn't been run since 1979!

    Good old vapour steam...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Lucas
    Lucas Member Posts: 3
    Hot Water Rads

    Need advice on removing old hot water rads to do major floor repairs. More importantly, advice on shutting down the system.

    I have piles of experience with most handywork but have never before now had the pleasure of mucking with a hot water heating system. My wife and I have recently purchased an older home, not quite 100 years old, with exactly one of these systems. The home was in significant disrepair and had not seen functional TLC for quite some time.
    The boiler is gas fired and was replaced probably 20 to 25 years ago. Pipes and rads are definitely originals. They have just shy of three zillion coats of paint I think. From what I can figure, the system has supply and return pipes connecting the rads to the boiler. Pipes are teed every which way from the supply to the rads and teed every which way back to the return ulimately ending in one supply and one return at the boiler. There is an expansion tank (somewhat resembling a barbecue propane tank with a red plastic plug at the bottom) hanging near above the boiler with a label on it describing that it is pressurized and contains a diaphragm.

    The water feeds like this : from the street horizontally, there is a shut-off valve followed by some sort of tee fitting scribed "inlet" with the tee end aimed down and scribed "vent" with nothing connected to it. Continuing horizontally there is a cone shaped fitting with a bolt sticking out from the top (pressure regulator of some sort?). Next there is another shut-off valve. The line then tees off. One heading to the expansion tank described previously and the other connecting to the pipe which I believe to be the main supply from the boiler. Oh, there is also what I think is a pump (vibrates and hums ever so soundly) which is patched into the return pipe to the boiler. Bear with me, my guess as to which is the return and which is the supply could very well be backward.

    How does this sucker work and how do I shut it down to temporarily remove a rad!? I am hesitant as I am not sure how to add water once drained. We still have a few cool weather spells ahead of us here. Does the entire system need to be drained to avoid major spillage from individual rads? If so, how does it drain?

    Any assistance would be great.

    Thanks and God bless.

  • Lucas
    Lucas Member Posts: 3
    Thanks a ton! But.....

    If I close the valve before the regulator, will this do the trick or is there something to be done at the regulator itself? There is also a second shut off valve just after the regulator. Would closing this one be enough or should I close them both (before and after the regulator)?

    What should I be looking for at the boiler in order to drain the system down and does anyone have any tips on how I might know when enough water has been drained? My home is three floors (including the basement) and a loft; all with radiators. The rad that I need to remove is on the main floor (immediately above the basement) so there is another floor and a half above.

    When I re-open the valve, will the regulator return appropriate pressure to the system again (assuming that I have bled air from it) or is ther something in particular I will need to watch for or adjust?
  • Big Ed
    Big Ed Member Posts: 1,117
    Radiator 201

    Shut the valve before the feed for safty sake.You may have a second valve after the feed wich would be your safety relief valve.....

    First floor radiator , might as well hook up a pump and drain it down completely.....

    You should able to just open the feedvalve and it will go back up to it's original pressure.If it is old it would be slow.If not ,best off replacing the valve. You will need about 12-15 #.
  • Lucas
    Lucas Member Posts: 3

    Thanks again.

    I'll start early this week and keep you posted. It sounds like I should do as much of the peripheral work as possible before filling the system again which means at least a few solid days of work. It's calling for below freezing by evening tonight, but supposed to warm right back up by monday.

    Take care and God bless.
  • Brian Macdonald_3
    Brian Macdonald_3 Member Posts: 5

    Check out the post titled Lucas Rad Removal. Good luck!
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