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50's copper radiant system with a leak

I have a customer with a copper radiant system that is leaking at one spot.

The system has copper running in ceilings and floors, gypsum in the ceiling, concrete in the floor.

This is a residential home with construction similar to what i would see in commercial applications,  Steel beams, support metal corrugated panels that support concrete that the copper is run in.  There is wood and tile above that in the kitchen. 

I know the approximate area of the leak.  I am looking for suggestions on how to access the piping.  From areas that we can see the pipe it appears that the copper runs within the corrugations, so my first thought was to try to remove the metal panel below and try to fix from beneath, The customer is already planning on a new kitchen floor so I have the option of coming from the top.

Thinking outside the box could i run a stop leak like in a automotive radiator system??? 

Any and All thoughts would be appreciated 


  • STEVEusaPA
    STEVEusaPA Member Posts: 6,506
    some thoughts...

    1.  I would let the system get cold, then fire it up and use an IR camera to pinpoint the leak.

    2.  I would go in from the top.  I cant imagine finding it from below, cutting the metal pan, then jackhammering up.

    3.  If it's leaking in one spot, I feel there's a good chance it's going to fail in others.  Maybe time to run new pex, and I would do it in the ceiling.

    4. If the homeowner just wants a repair, and they are doing new ceramic tile floor, tell them to buy double the amount and store it, for future repairs.

    5.  Sorry, no leak stop.
  • McMaster
    McMaster Member Posts: 28
    Other methods for locating the leaks

    I have found and 'excavated' a bunch of leaks in concrete. The IR camera is a good way to go, but a more low-tech approach is to isolate the line, then run soapy water through it with a transfer pump. What I have done is before you run the pump (but have it all set up), get extension chords set up so you can be about where you think the leak is BEFORE you start the pump. Be sure the house is dead quiet. Then, when you are leaning over about where the leak is, connect the plugs of the extension chords together which will start the pump. You should be able to hear a rush of air before the water hits. Once you do, unplug the pump and listen carefully. You should be able to hear it sucking in air. This works quite often. Of course, the other method is compressed air. Sometimes you need a combination of both. But either way, I've been able to very carefully pinpoint leaks with a high degree of accuracy.

    For digging out, you can use a SDS rotary hammer drill in the hammer mode to dig out the concrete. Use care and work around where the line is. This is where an IR camera comes in handy, so you don't booger up adhacent lines. I don't use an IR camera, but if you work slowly you can usually excavate w/o daming adjacent lines. But not always, then you've created more work for yourself.
  • hot_rod
    hot_rod Member Posts: 22,143
    another thought

    if the copper was installed on the galvanized 'span-deck" and that is getting wet from a leak good chance you will get some additional galvanic corrosion.

    50 years seems to be good life expectancy, it might be time to start thinking on a Plan B.

    I'm not sure I would fix one leak and install a new tile floor over a 50 year old system?

    Maybe a thin dry system could be added over the top? Viega and Uponor have these systems available.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
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