3/4" supply to shower?

Discussion in 'Shower & bathtub Forum & Blog' started by Patrick North, Mar 1, 2010.

  1. Patrick North

    Patrick North New Member

    Messages:
    2
    Location:
    Bellefonte, PA
    Putting in a bathroom on the third floor and I’m a little anxious about shower water pressure. The shower stall will only have a single head- no multiple heads, jets, etc.
    My question is- all things being equal- will I improve anything by piping ¾†lines to a ¾†mixer as opposed to ½�
    If I used ¾†supplies/mixer I’d also try to keep the shower head at ¾â€. Would I lose all benefit of the ¾†supplies if I went down to ½†shower head?
    While I’m at it- any recommendations for a ¾†combo mixer/volume control valve, or is there no such animal without spending $$$$?
    Thanks,
    Patrick
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,059
    Location:
    New England
    Unless this will also have a large tub, then you would have no benefit from a 3/4" valve with one showerhead. Now, running 3/4" up into the area would help ensure there was enough water for that bath, but it won't make much of any difference to the individual valve for the shower. To maximize things, you could reduce it to 1/2" at the valve, but that probably wouldn't be necessary either. The longer the run, the more friction, the lower the flow and pressure while running (pressure with no flow would be essentially normal). But, if you run 3/4" to the immediate area, the reduction to 1/2" for the valve should be fine.
  3. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,351
    Location:
    Yakima WA
    Another point to consider is that it takes a very long time to purge cold water from a 3/4" hot water line compared to the same length of 1/2" line.
  4. Patrick North

    Patrick North New Member

    Messages:
    2
    Location:
    Bellefonte, PA
    Recirc to the rescue!

    Yes, especially because this bath is on the third floor (and because the plumbing is all new) I"ll be adding a Grundfos HW recirculator.
    Thanks for the assurance- a 1/2" will sure be a lot less $$$!

    Any recommendations on valves?

    Thanks,
    Patrick
  5. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,059
    Location:
    New England
    Many like the Delta 1700 rough-in valve...your choice of guts to put in it and trim. That rough-in will allow you to use a thermostatic valve, which I prefer. Personally, I've used and like Grohe, but that can be a problem if you don't have local suppliers. You can get Delta stuff nearly anywhere.
  6. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,689
    Location:
    Cave Creek, Arizona
    Larger pipes do NOT increase pressure, only volume. If they are extremely long with a high velocity flow rate, then larger pipes will not LOSE as much pressure, but that is seldom the situation with the average home shower faucet.
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