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UNDERSLAB LEAK

Marc Zitcer
Marc Zitcer Member Posts: 1
Hi all!

Wondering if anyone has tips for locating an underslab leak in a baseboard loop system that doesn't involve ripping up carpets or injecting radioactive isotope into the system!? Chances are this is a pretty good size leak 'cause it zero's the boiler pressure in no time when the fill valve is shut. No evidence of leaks where the risers come up through the slab and no visible washing away around the exterior slab perimeter.

Any help will be appreciated.

Comments

  • Rich daplumber
    Rich daplumber Member Posts: 14
    TRY A CAT

    I WOULD PUMP UP THE LOOP WITH HIGH PREASURE AND LISTEN CLOSELY.

    AT A WIRSBO CLASS I WAS TOLD THAT A CONTRACTOR HAD A FAT OLD CAT.
    HE WOULD PUMP UP THE HEAT, LEAVE THE CAT FOR AN HOUR AND LOOK WHERE THE CAT WAS LAYING. THERE WAS THE LOCATION OF THE LEAK.
    I HAVE ALSO HEARD OF USING HELIUM FOR LOCATING LEAKS IN SLABS.

    MY FAVORITE IS THE CAT, ANYONE GOT ONE?
  • Constantin
    Constantin Member Posts: 3,796
    Dan Holohan mentions a couple in his book

    The cat was the preferred method for carpeted areas. Nowadays, you could also substitute a thermal camera to look for the "bloom".

    The housewife approach in Levitton was wiping the slab with water. Wherever it evaporated first were the tubes/leak.

    The plumber approach prior to the housewife discovery was to listen for the leaks' whistle via a screwdriver held on the floor. A stethoscope might work also.

    If it was up to me, I'd use a thermal camera, likely the most reliable approach these days.
  • hr
    hr Member Posts: 6,106
    Is this a job

    you would like to undertake yourself? If you have the tools and time it may be possible... but :)

    Having tried all the various methods, except the cat! I now hire the experts. It is much better use of my time and my customers money.

    www.leakbusters.com arrives with a truck load of high tech equipment and a very skilled operator. They have never let me down. Generally about $250.00.

    In every case they marked the leak to within inches of where I chopped the concrete and found the leaks!

    Not sure about the carpet, however. Removing and reinstalling carpet is not a big deal. You will need to remove it to chop the slab and repair the leak anyways.

    That being said, the age and materials used should help you decide if the job (pinpoint, expose, and repair)is worth attempting. An ocassional leak is one thing but a slab full of old copper or steel that is leaking may dictate plan B.

    Good luck, let us know how you fare.

    hot rod

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
  • Weezbo
    Weezbo Member Posts: 6,232
    hello . Um...how old is this system?

    Young...? then maybe you need to pre purge the lines, all the lines.
    old...? Need to pressure and isolate the lines,....Allthe lines.
    older yet...? metal pipe? rubber? may be looking at instant repeat like Hot Rod says. Is it live or is it memorex? find one fix two like that. ok after the twelfth leak surely that will fix it..... nope...:( i was sure that would been the last one:)
  • Weezbo
    Weezbo Member Posts: 6,232
    hello . Um...how old is this system?


    older yet...? metal pipe? may be looking at instant repeat like Hot Rod says. find one fix two like that. ok after the twelfth leak surely that will fix it..... nope... :( i was sure that would been the last one:)
  • Weezbo
    Weezbo Member Posts: 6,232


  • clammy
    clammy Member Posts: 3,089
    copper slab leaks

    I,ve run into this promblem a few times especally in bi levels with finished basments usally in most cases we just re do the basement loops over and remove them completly usally when it's copper under groundyou fix one and as time goes by another one will appear in the long run i feel that copper loops in a slab unless properly insulated will fail and yes i know there are cases where systems are around forever that never leak but in short by the time some one realizes that you have a under ground loop leak your boiler has ran through a ton of water and all the fresh water do no boiler any good these are just my feeling .I earlier in my life rough in these type of grond loops and in most cases iit was done this way to save time and time is money so alot of guys still do this because it is the easiest way and time is money .have you looked to see if your slab have cracks or settling marks in it it may be time to just re pipe it and never have this issue re appear just my opoin peace clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • ernie_3
    ernie_3 Member Posts: 191


    In the winter hot spots are the sure indicator on the general location of the leak. Better off cutting off pipe and running "above ground" if thats doable
  • ernie_3
    ernie_3 Member Posts: 191
    A under slab

    In the winter hot spots are the sure indicator on the general location of the leak. Better off cutting off pipe and running "above ground" if thats doable
  • Mechanics Stethescope and air

    We find plumbing leaks in pool plumbing. If you can pressurize the system with air, and enough water leaks out, so that air now passes through the leak, it will bubble in the water that surrounds the leak. This bubbling is much noiser than just water leaking out. Go to the auto parts store and get a mechanics stethescope, they're cheap, but work well. You will probably find it....
  • Ken D.
    Ken D. Member Posts: 836
    Slab leak

    I like the wet mop method for bare floors. Although it is not the best in warmer months when the heat is not running. I have used an Amprobe (ATP) ultrasonic leak detector that is usually used by HVACR guys with good results. One or two leaks I will fix, but any more than that either put in new pipes with thinset or run baseboard.
  • Bucky_2
    Bucky_2 Member Posts: 9
    As mentioned previosuly...

    ...the thermal imaging camera is a good option...but here's a suggestion if you don't have one lying around: do you have any friends in a volunteer fire company? Many FDs these days have the cameras....and if you have a friend with 'rank' or in good standing, usually they will be allowed to borrow the camera for an hour or so (as long as they agree to stay with the camera and IMMEDIATELY respond with the camera to any fire calls that may occur during this period).

    Membership HAS its privilege!
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