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Preparing old radiators for hot water

Robert_HRobert_H Member Posts: 135
In advance, I am NOT converting my house from steam to hot water!

I am replacing my old forced hot air system with a gas fired hot water system and old radiators.  I will probably ask more questions but for now I am refurbishing the radiators which were recently removed from a working system.

 The radiators are tube type (4 and 5 tube).  4 are Gurney Copley and one is an American Radiator model.  They all have one inlet open (fitting removed) with three more ports plugged.

Pressure Test

Although they came from a working system I don’t want to assume that they don’t leak. There is plenty of references on the web about pressure testing them in place but I need to test them standing by themselves, in my back yard.  How can I test them in my yard?  The obvious easy way is to put fittings together to leak check them with a garden hose, for a few hours.  My house is two stories so the system pressure will be around 12 PSI if what I’ve found so far is correct.  The water pressure in my house was 52PSI the only time it was ever checked.

Outlet Location

What’s the best location for the outlet fitting if the inlet is on the bottom?  It makes sense to me that the outlet should be on the top of the opposite end but there may be factors that I am not aware of.

Plug Removal

As I expected the large plugs have become one with the radiators.  Before I chase down a big enough torch to heat the area enough to free the plugs, I would like to try an impact wrench.  Not having done much work with cast iron, is this safe? As in, can cast iron crack under the impact?

Internal Cleaning

Inspection with a flashlight shows some surface rust and I understand there may be sediment in the bottom.  Should I fill them with a TSP solution for a few days and flush them out then neutralize them?  Or?  




  • RobGRobG Member Posts: 1,850
    Re-using Rads

    Can you post pictures of the radiators? Some steam radiators will not work with hot water systems.

  • SteamheadSteamhead Member Posts: 11,379
    edited May 2013
    Most tube type rads

    will work with steam or hot-water. But I've seen some very early American Radiator ones that were steam-only. Best to post pics.

    I would avoid testing them with air. Water is much better since it is non-compressible, so if something lets go there's far less chance of an explosion. Test them to 30 PSI for at least 15 minutes. That's the highest pressure your system will ever see, assuming the safety valve is working as it should. If they pass this test, they're fine.

    Either connect both the supply and return pipes on the bottom, or have the supply at the top of one end and the return at the bottom of the same end. Use whichever setup is best for the way the pipes must run.

    An impact wrench is great for getting plugs out, but I'd heat the radiator around the plug tapping first to make it even easier.

    Then rinse them out with water and you're good to go.
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
  • Bob Gagnon plumbing and heatingBob Gagnon plumbing and heating Member Posts: 1,344
    edited June 2013
    Heat The Area Around The Plug

    With your torch, heat the area around the plug until it's very hot,  then hold an ice cube on the plug for about 30 seconds, then quickly apply the wrench and work fast to get a couple of turns. This usually works for me, sometimes you get a turn, and the plug gets too hot and tightens up again, apply heat and ice cube again.

    Thanks, Bob Gagnon
    To learn more about this professional, click here to visit their ad in Find A Contractor.
  • Robert_HRobert_H Member Posts: 135
    Thanks and Pics

    Thanks for all the help. I did get two plugs out with the impact wrench last night. I don't have a torch with enough volume for this kind of heat but I have a gas forge and I can use the one of the burner as a torch for this kind of thing, it just takes a little while to disassemble...

    the black rad is one of the Gurney Copleys and the silver on is the American Radiator Co.
  • SteamheadSteamhead Member Posts: 11,379
    They'll work fine

    with hot-water. 
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
  • Robert_HRobert_H Member Posts: 135
    edited June 2013
    Leak test

    I ran a leak check on the rads yesterday and only one had any leaks. The last one I tested!!! I consider myself lucky.

    The leaks are at the bottom between the sections and where the leaks are I could reach in and feel that the threaded coupler was somewhat dissolved in those areas.

    Sandblasting today
  • SteamheadSteamhead Member Posts: 11,379
    edited June 2013
    I think I see

    a rod in that leaking radiator that holds the sections together. Is it one of the Gurneys?

    If so, it uses push-nipples between the sections, not threaded ones. These are easily replaced if you can source new ones.
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
  • Robert_HRobert_H Member Posts: 135
    Yes, its one of the Gurneys

    There are 4 rods on these, two on top and two on the bottom.

    Ill look around for parts.

  • JeffGuyJeffGuy Member Posts: 70
    What about

    How are you going to prepare/flush out the interior? I have some old rads I bought that I want to do the same thing with, but there is a lot of crud in the bottom. Are you going to go with TSP or is that not needed?
  • Robert_HRobert_H Member Posts: 135
    Steamhead said:

    "rinse them out with water and you're good to go."

    so far I have flushed all of them until the water runs clean and left an inch of water in the bottom to soften things up and Ill flush them again.

    I read somewhere about including a sediment trap type filter in the return line when using old cast parts. However, I still haven found where I read it.
  • SWEISWEI Member Posts: 7,356
    Sediment removal

    Check out the Caleffi Dirtmag.

    I'd also flush the system twice using something like Rhomar Hydro-Solv, then add some inhibitors and protection for the full fill.  Check again in a year and see what the water looks like.
  • RodRod Posts: 2,067
    edited June 2013
    Push Nipples

    Hi- If you need radiator push nipples they are available from Oneida County Boilerworks

    - Rod

    Oneida County Boilerworks

    611 Mortimer Street

    Utica, NY 13502

    (315) 732-7914
  • JeffGuyJeffGuy Member Posts: 70
    edited June 2013
    Moving vent

    After the cleaning (but before painting), are you aware that you should move the vent from the middle of the radiator (where it is now), to the top of the radiator? Hopefully there is a threaded tap up there (though I don't see one in your pics). If not I guess you can drill a hole and tap one. If you leave the vent where it is now then it won't purge completely once filled with water.

    The big plugs at the bottom of my radiators came out pretty easily (as did yours). I'm more nervous about removing the small (1/8") plugs that my rads provide at the top for the vents, since they have flat head screwdriver heads and look pretty easy to strip.
  • Robert_HRobert_H Member Posts: 135

    Ordered push nipples today.

    Jeff, each one has a boss at the top so i can drill and tap for the vent. you can see it in the pic of the black radiator.
  • Robert_HRobert_H Member Posts: 135
    Time to reassemble!

    All of the radiators have been blasted, flushed and painted and now its time to put the one leaker back together with the new push nipples. I'm assuming no sealant on the nipples, just leave them bare.  I'm reading mixed reviews on whether I should put sealer on the the mating surfaces around the push nipples.

    Any experience, sealant or no?

    Also How tight to take the draw bars. I can find no assembly instructions for push nipple rads. Lots of info on new screw types from England though.


  • Paul PolletsPaul Pollets Member Posts: 3,022
    Doping the nipples

    Sounds exciting....

    The push nipples are lightly coated with Pro-Dope, and inserted into the section(s). The radiator is then pressed together using (2) 5 or 10 ton jacks spaced equally apart using 2x8 wood blocks between the radiator and the jacks. The threaded rods are installed after the press and re-tightened.

    My father used to have a CI radiator assembly room in the back of his supply house in NY. I can remember putting many together as a young teenager.
  • Robert_HRobert_H Member Posts: 135

    I think I can cob something together that will do that.

    Thanks Paul
  • Charlie from wmassCharlie from wmass Member Posts: 3,922
    The radiator assembly room would be nice

    I use threaded rod and tighten them even and steady.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
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