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Repairing hydronic floor heat leak in concrete

JoshWJoshW Member Posts: 2
I have a 1953 home with hydronic floor heating that was abandoned in 2006 due to leakage. I have been looking for a product that may help and I think I have finally found one but can not find anyone with experience in the English-speaking world to help....

The system is iron pipe (or maybe mild steel) in concrete floor slab-on-grade construction with two zones. I have removed the furnace and pumps to make room in the utility room but would love to revive the system if possible. I always thought that a good de-scaling product followed by an aerobic sealer of some sort --like fix-a-flat for pipes may do the trick.

My brother is currently stationed in Austria and his landlord had some plumbers come over to do some repairs to an old hydronic system with radiators in a 100+ year old building and they pumped this goop into the lines for 6-7 hours to seal them and then purged the lines. he took a picture of the stuff they had and it was from a company called BaCoGa

Anyone have experience with this stuff?

More pictures of the old system here


  • hot rodhot rod Member Posts: 7,080
    any idea

    how large the leak is? Maybe put a water meter on the fill system for a few days or a week.

    My experience with old steel pipe radiant jobs is entire sections of the pipe rust away where they touch the sub fill material. Especially in areas where it may have been wet from a leak or ground water.

    In one case the bath tub trap had leaked for years and rusted away several feet of the steel pipe when we cut open the slab.

    If the pipe was held up and completely encased in the concrete it survives better. It is tough to keep every foot of pipe up in the slab when they pour and some installers actually put the pipe up on wood block to try and keep it centered in the pour.

    It's rare to find just a pin hole in a system that old. But a sealer can work if you determine it is just a small leak at a weld or threaded joint.

    I have have good luck with the sealer made by Fernox on some old rubber tube jobs.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • JoshWJoshW Member Posts: 2
    Not sure on how large

    Not sure on how large the leak is as the system was abandoned in 2006 -- many years before we bought th place. The neighbors said that the system was fully functional through 2005 but then some renters had problems and what sounds like a large leak but who knows. The neighbor said the house 'practically floated away' but she is highly prone to exaggeration and probably doesn't even know what year it is so....

    Unfortunately, the boiler, pumps, and fill lines have all been removed and discarded to make room so any testing will have to be rigged with new fittings and a bit of work.
  • GordyGordy Member Posts: 7,122

    Test the piping with air pressure. Couple of shrader valves and an air compressor. Buy brass adapters to go from existing pipe size to shrader valve on the supply side, and put a psi gauge on the return side of the loop in question.

    If its all drained see how many psi leaks off in a given time span. If you can't get it to hold an air charge you know the leak is large.
  • SWEISWEI Member Posts: 7,356
    Somebody posted a link

    to this awhile back

    No experience with them, but it does look interesting.
  • RichRich Member Posts: 2,243
    I beleive

    that we must imagine whatever has caused the piping till now to deteriorate is still happening .  So if we line the pipes at some point will the lining be all we have restraining our fluid ?  I think we are expecting a band aid to close a gaping , sucking chest wound .  Is this a good idea ? 
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC 732-751-1560
    Serving most of New Jersey , Eastern Pa .
    Consultation , Design & Installation
    Rich McGrath 732-581-3833
  • SWEISWEI Member Posts: 7,356
    It depends

    on what caused the damage and how it is remediated.  This would require a knowledgeable applicator and some skill, but I for one would happily pay for that if I had enough buried pipe.
  • GordyGordy Member Posts: 7,122
    Leak size

    I think if you pressurize the loop in question to say 100-150 psi with air you could tell from the loss of pressure over a certain amount of time what you are dealing with. Plus taking it to a high psi could pretty much determine if there were some areas ready to blow out that may not have under normal system pressure in a hydronic system.

    Bottom line if you can't even do a pressure test abandon it.
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