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5/8 pex leak in concrete

i purchased a fixer upper, im finishing a half built garage , noticed 3 5/8 pex stubs on either side of the garage, and 2 sets in the back of the garage.
researched and found 5/8 is not common, fittings are hard to find and primarilly used for heat.
i filled each run and shop vac the water out. calculated each pex run to be about 100 to 180 feet.
the third run doesnt hold water or pressure.
it holds about 3/4 gallon so probably around 100 feet.
would it be practical or effective or even possible to snake 3/8 pex through as a sleeve instead of abandoning this loop?


  • austinhealeyaustinhealey Posts: 6Member
    … i hooked up an LP on demand HWH and a sump pump in a 5 gallon bucket and connected the loops in series to test the buried PEX lines and after a half hour there were 78 degree spots throughout the floor.
    after and hour or so the floor was averaging 68 to 71 degrees throughout using my infrared gun. my hypothesis that it was radiant heat looks good so far. Its either radiant or he set it up for a carwash and needed to bury 300 feet of extra pex.
    ****i still cannot grasp the layout. garage door entrance there are (3) 5/8 stubs on the left wall, all grouped together. on the opposing wall (3) stubs.
    toward the rear or opposite end of the garage (Far side away from the garage door) are (2) stubs left side and (2) 5/8 stubs on the right wall.
    the 3 and 3 in the front trace to each other on both sides.
    the 2 and 2 are also independent of each other. so a total of 5 loops spread out
    I can place my HWH next to the (3) stubs, do the opposing (3) stubs with (2) in series and add a T with a mixing valve??? what about the 2 loops that are 30 feet away?
  • John RuhnkeJohn Ruhnke Posts: 871Member
    Could it be a snow melt system? Does anything run to the driveway?
    I am the walking Deadman
    Hydronics Designer
    Hydronics is the most comfortable and energy efficient HVAC system.
  • austinhealeyaustinhealey Posts: 6Member
    John. its not, the driveway is stone, and was nonexistent before I moved in. and buried under an inch of soil.
    I excavated the topsoil before having 30 ton of stone delivered
  • John RuhnkeJohn Ruhnke Posts: 871Member
    edited October 9
    Looks like you got a nice radiant slab there. What kind of heat is in your house? I might just forget about the loop with a hole in it. Maybe do a heat loss and after some figuring you could find out if the slab will heat the room without the broken loop. Before I got to crazy I would want to see it hold a 50psi test for 24hrs. tie all the pipes together with fittings and test.
    I am the walking Deadman
    Hydronics Designer
    Hydronics is the most comfortable and energy efficient HVAC system.
  • austinhealeyaustinhealey Posts: 6Member
    The house has a oil fired furnace that does domestic lines and radiators.
    i bought a LP on demand HWH from china i plan to use for summer domestic crossover , thats what im testing with.
    i dont know what a heat loss is but im still building the structure, i am capable of making it airtight and r-19 i used 2x6s.
  • John RuhnkeJohn Ruhnke Posts: 871Member
    You could do a radiant zone off that boiler. Are you going to do this your self? or find a hydronics contractor?
    I am the walking Deadman
    Hydronics Designer
    Hydronics is the most comfortable and energy efficient HVAC system.
  • austinhealeyaustinhealey Posts: 6Member
    John I do everything except HVAC and concrete, I'm pretty capable of doing anyting general contractor here license in the state of Pennsylvania I just don't know anything about radiant heat I've never dealt with it.
    I'm guessing the boiler in the basement would be 120 ft away and I don't think that would be practical unfortunately there are two 1 inch well line stubbs in the garage that I haven't figured out what they're for yet so maybe they go to the basement somewhere already. It's a detached three car garage btw
  • HomerJSmithHomerJSmith Posts: 554Member
    You can forget about snaking a 3/8" line thru a 5/8" line, ain't never goina happen. It can be repaired if you can isolate the leak and there's the rub. Repairing pex in concrete is difficult. You almost need a thermo camera with hot water going thru the circuit. Is the pex, type A or type B? How do you know it is 5/8" pex? Did you read the markings on the pex? Just asking.
  • hot_rodhot_rod Posts: 11,773Member
    There are some hydronic sealers available. I have had mixed results with them Pinholes maybe, not a ripped tube
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • austinhealeyaustinhealey Posts: 6Member
    I purchased a 200 foot electrical fish tape and role of fish wire, snake the fish tape through pulled the fishing wire back through drilled and secured the 3/8 PEX and lube the line as we pulled from one end and pushed from the other and were able to repair the two loops fyi if anyone runs into this situation.
    It seems to take a bit longer to heat the concrete in this area but definitely works
  • Intplm.Intplm. Posts: 845Member
    Well ! @austinhealy ! That is terrific that you laced 3/8 pex in the 5/8.
    I'm surprised at this because the turns and bends that are commonly in this type of installation are very tight and hard to , if not impossible too snake another pipe through. So congratulations on that.
    As you may know, the reason why it takes a bit longer to heat up is because the 3/8 is insulated by the 5/8.
    Good for you on correcting that leak this way.👍🏼
  • nibsnibs Posts: 342Member
    @austinhealey Well done, how did you fasten the new pex to the pull wire a pic would be great.
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