(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 3 of 3

Thread: Variable flow volume control with a 2.5 GPM head

Hybrid View

  1. #1
    DIY Junior Member let it flow's Avatar
    Join Date
    Jun 2011
    Thousand Oaks, CA

    Default Variable flow volume control with a 2.5 GPM head

    Will I need a variable flow volume control for my new 2.5 GPM shower head? Or will it work OK to just use the on/off feature of a pressure balanced temperature mixer?

    This will be going into a remodel with new piping. Right now I have a seperate hot and cold valves that mix at the divertor and then goes to a showerhead that could sink Noah's ark. But I am sure the permit inspector will make me install a 2.5 (or lower!) GPM head, as well as replace the valve with a temperature contolled one. It seems that the low flow head will need all the pressure it can get, in order to spray right, with enough "blast" pressure and water volume to rinse the soap off. I suspect that a volume control valve would be turned wide open most of the time. I also suspect that a useful volume control would need to have a pressure/flow characteristic that closely matches that of the head, in order to get a flow that changes evenly over the full rotation range of the valve.

    Give me your thoughts and experiences of using just an on/off control. Is the spray sometimes too much like "stabbing needle" jets?
    How do I go about choosing a valve with the appropriate pressure/flow curve? Valve spec sheets don't even touch that issue.

  2. #2
    Moderator & Master Plumber hj's Avatar
    Join Date
    Aug 2004
    Cave Creek, Arizona


    A SINGLE shower head does NOT need a volume control and ANY installation which uses "positive" shutoff volume controls also needs a control unit with integral check valves. However, a valve with a single handle usually only controls the temperature, the volume is at full flow as soon as it is turned on. A Delta 1700, for example, has one "set it and forget it" temperature lever and a coaxial second on/off volume control handle.

  3. #3
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    New England


    Code requires antiscald...it does not dictate how that is achieved. that can be either pressure balance or thermostatic. A thermostatic may have a pressure balance in it as well, depending on its response rate to changes in temp and pressure.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

Similar Threads

  1. Variable Volume Pressure Tanks and Aeration
    By howens in forum Pumps and Tanks Well Forum & Blog
    Replies: 6
    Last Post: 06-03-2011, 04:39 AM
  2. Woodford Iowa variable flow 205C --Replace or Repair?
    By DonJack in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 0
    Last Post: 03-31-2010, 12:40 PM
  3. Variable Speed/Flow pumps and energy usage
    By bartman99 in forum Pumps and Tanks Well Forum & Blog
    Replies: 11
    Last Post: 02-20-2010, 04:27 PM
  4. electric variable flow valve
    By Tinmaniii in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 11
    Last Post: 10-19-2008, 07:17 AM
  5. Volume control in line between PB valve and shower head
    By jkhome in forum Shower & bathtub Forum & Blog
    Replies: 3
    Last Post: 11-05-2004, 12:55 PM


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts