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Help- Plumber with limited hydronic exp. needing advice

You can buy Dresser couplings that will handle up to
200°F water. There are special gaskets required to handle that temperature. We have used them for, "emergency buy me some time until spring", repairs.


  • Larry F.
    Larry F. Member Posts: 3

    Help- I'm looking for advice on doing a piping repair. i'm a plumber w/ not much experience with heating systems. The system is in an apartment complex approx 45 years old. Hot water heat/ chill water cooling. Small fancoil units are in the ceiling of each apartment.Piping has leak in the attic on one of the main runs. old steel pipe is very corroded, and deteriorated. complete replacement has been discussed but is not feasible at this time so we are going to attempt a repair to the leaking section. My questions are:
    1. I dont believe we will be able to unscrew piping from fittings- looks to weak and rusted. Is it possible to use steel dresser couplings to couple new pipe to old? Will the rubber gasket take the heat? The maint person says he is running 180 degree water through the system. Is this a normal temp? Also what would a normal pressure be for a system like this?.
    2. There will be a tee involved in the repair. This tee is 2" x 2" x 3/4. The 3/4 side is branching off to one of the fan coil units. not sure if it is the supply or return. Are these just a normal tee, or are they some kind of "diverter" tee that sends water to the fan coil unit?-Thanks Larry F. Roswell NM
  • ScottMP
    ScottMP Member Posts: 5,884

    Larry are yousure this is what you saw ? It could have just been a weather ballon !

    O.K. only kidding.

    Preasure in the system will/should be related to the height of the building.

    Its very possible that these are normal tee's and you have a two pipe system.

    I would stay away from the couplings. If the piping is that bad then it needs to be replaced anyway. Any work you do will disturb it and you are "Married to the Job".

    Back it out untill you get to good fittings and if you comfortable re-do it in copper with insulation. Install ball valves right off the tee's so you can isolate and work on your section if need be.

    If it is a diveter or monoflow tee then it is normally installed on the return.

    Take some pictures and ask all the question you need.

    Good Luck


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  • Al_19
    Al_19 Member Posts: 170

    If the piping is in the attic, there may be anti-freeze in the system.
  • Jamie_6
    Jamie_6 Member Posts: 710


    The best route to go is to replace the piece of corroded pipe and figure out why it is so corroded. Maybe you have an underground leak somewhere and your system is letting in fresh water.

    If pipe wrenches don't seem feasible maybe it's time for some sawzall surgery. (A grinder might be necessary also). Maybe the replacement piece of piping could be done in copper to eliminate any more stress and movement on the pipes during the instillation process!

    As far as the required water pressure for the system we need to know the foot print of the building and how tall it is.

    The last question about the tee is something we would need to see. Maybe you could post a picture of the tee itself. Personally I've never seen a black diverter fitting but I'm still only a puppy!


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  • Wd-40

    on the threads, maybe some heat on the fitting with ice on the pipe, and don't be afraid to secure up the piping that is going to stay, with F + M rings, to prevent more damage. Bob Gagnon

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  • amhplumb_2
    amhplumb_2 Member Posts: 62
    Victaulic Roust-A-Bout Coupling?

    If you are able to get some "decent" plain ends after you cut out the corroded section, you might want to consider using Victaulic Roust-A-Bout Couplings. Consult with your Vic rep about your particular situation. Iv'e used them in the past and they work great. As adviced by another post, you could end up "married" to this job, I would make it clear that this is probably only putting a "bandage" on what could be a major problem! Get it in writing! If a major leak shows up somewhere later it may come back to "bite ya in the @#$!" Good Luck!
  • Rich Kontny_3
    Rich Kontny_3 Member Posts: 562
    Lots of Variables


    Do you want to trial and possibly error with this situation or do you want to get a trusted or well respected hydronic person in to actually work with you and therefore teach or add to your experience!

    This certainly does not sound simple (cooling towers usually do not have 180 degree water piped to them except at power plants) It sounds like you are on the picked up heating loop after the heat pump kicks up the temperature.

    Cooling towers come in various shapes,styles and with several heat gain sources (steam, hydronic,electric and even ground source)

    As a novice (willing to learn) I would suggest that you call in a seasoned professional as this could easily be a can of worms that you are exposing yourself to.This is where Murphy's Law usually shows up (whatever can go wrong does)

    Get professional help with this one!

    Good luck!

    MP 1969
  • bob young
    bob young Member Posts: 2,177

    sounds like a very valid point,Rich. always helps to know & understand the system you are cutting into to. otherwise disaster could be lurkingin the shadows.
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