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Manifold Set Up-PRI/SEC

stev0 Member Posts: 11

Plumber just getting into hydronics. Installing a Buderus GA124 cast iron boiler, 80,000 btu output. Was wondering if you see any problems with this piping set up. Primary loop and manifolds all in one inch then reduce to 3/4 inch going out up to baseboard zones. There will be one more zone added to this pictured manifold. Is there any problem with the pipe size or design? Thank you for any information.



  • JStar
    JStar Member Posts: 2,752
    Not bad.

    I would double check the manual, but most manufacturer's want the boiler pump to be on the return, and the air scoop/expqnsion tank on the system loop before the pumps. That way, both pumps are pumping away from the point of no pressure change (the common piping).
  • stev0
    stev0 Member Posts: 11

    buderus gives no piping specs in manuals! the pri circ is punping away from exp tank in pri loop
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    air scoop/expansion tank on the system loop before the pumps

    Mine agrees with you. But it seems wrong to me.

    My boiler loop runs at three maximum temperatures, depending on what is calling for heat.

    175F for the indirect.

    135F for a baseboard zone.

    120F for the radiant slab zone.

    But the maximum for the system loop is 135F, and most often 120F. And that can go down all the way to 75F in warmer weather.

    Now for the "air scoop" (actually, a Taco microbubble absorber), that works the best with the hotter temperatures, this means it takes a long time to get all the very little bubbles out. If the thing were in the boiler loop, it seems to me that the microbubble absorber would be more effective.

    Why do you suppose they recommend putting the thing in the system loop? It is true that in my installation, it would have been difficult for geometric reasons to put it there.
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