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bleeding a heated slab?

my buddy's friend's sister's cousin asked me to come help bleed their heated slab hot water system.

not sure what i'm getting into, but are the air vents going to be at random places sticking out of the slab, or are they at the end???

They sent me this picture:


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  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
    That's no buddy....

    Yikes!  It appears you may have luck closing one loop at a time and purging it thru the near boiler piping, if there's a way to drain.  Of course if I were going there, between one and everyone of those would leak after I turned them.

    If there are vents they should be at the manifold, or in the near boiler piping.

    Why does it need to be bled now?  Are they sure there isn't a frozen loop, or a circ problem?

    Even if I had a 10 foot pole, I wouldn't touch it.

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  • TomM
    TomM Posts: 233

    haha steve!  yes, those manifold valves leak when you touch them.  Don't ask me how i know.  :-)

    it's an intermittent circ problem, plus a combination of bad piping, and the system needed to be bled.  the relay on the aquastat controller isnt staying closed for the circ.  I don't know who the hell wants to get the aquastat off though.  see pics.

    not sure how the designer made provisions to get air out of the radiant slab piping, there is really no way to purge the loops.  ???

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  • Paul Pollets
    Paul Pollets Member Posts: 3,656
    Copper loops

    Copper loops within slabs have a tendency to leak and ultimately fail due to the concrete alkalyds attacking the pipe from the outside in. I'd re-pipe the manifold to allow individual ball valves and a test port (boiler drain). Each loop should be tested yearly. Purging is not possible with the existing setup. The owners will need to invest in a better system....soon.
  • Pughie1
    Pughie1 Member Posts: 135

    Is that a "Levittown Job"?