(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 13 of 13

Thread: Pressure-balancing valve = cold water on the hot water circuit?

Hybrid View

  1. #1

    Default Pressure-balancing valve = cold water on the hot water circuit?

    Will a pressure-balancing valve feed cold water to the hot water side when the hot water side is open? I had my water heater disconnected this weekend, with water off at the main supply. When I reconnected the water heater, I had the cold supply valve closed when I opened the main supply valve. Went to the water heater to open it's supply valve, and could hear water rushing in, with the valve closed??? Went inside to check a faucet and sure enough, I had cold water at full pressure on both the hot and cold side -- while the supply valve was still closed at the water heater.

    I was told this was because of a pressure-balancing valve. Is this normal function for a pressure-balancing valve, or is there something else going on? I've only got one mixer valve (tub/shower) in the house - everything else is two-handled faucets.

  2. #2
    In the Trades Jerome2877's Avatar
    Join Date
    Aug 2009
    Location
    BC
    Posts
    384

    Default

    So the valve for the shower/tub was open for hot and cold? Then yes this would feed the water into the hot side and back the the WH. If it wasn't open then no this shouldn't happen.

  3. #3
    Plumber jimbo's Avatar
    Join Date
    Aug 2004
    Location
    San Diego
    Posts
    9,001

    Default

    It isn't the pressure balancing feature that does that . EVERY faucet...sink, tub, or shower performs the function of mixing hot and cold water. If you have any faucet set to a "warm" setting, or in the case of a two handle faucet, if you have both open, then water will cross over inside the faucet. In your case, cold water crossed over and back-fed the hot piping.

  4. #4
    Moderator & Master Plumber hj's Avatar
    Join Date
    Aug 2004
    Location
    Cave Creek, Arizona
    Posts
    25,624

    Default

    A pressure balancing unit does NOT interconnect the hot and cold. IF it is working correctly it will completely stop ALL the flow from the faucet if EITHER side is shut off, but will NOT transfer the cold into the hot side. You either have a defective faucet, or there is some other factor at work causing your symptom.

  5. #5
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,390

    Default

    A pressure-balance spool valve is a safety feature mandated by Federal regulations as one way to provide anti-scald technologies to a shower valve. It is designed to prevent a shower from getting excessively hot if the pressure on the cold supply side drops more than the hot side which might happen if someone flushed a toilet, or opened a heavy cold water use nearby. As mentioned, if it is working properly, at that valve, it would shut off the flow if the pressure on the other side dropped, not cross-over the supplies.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  6. #6

    Default

    Quote Originally Posted by jimbo View Post
    . . . In your case, cold water crossed over and back-fed the hot piping.
    All fixtures where closed

  7. #7
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,390

    Default

    If a single handle faucet's cartridge is defective, if it can be left in a middle position, you could get cross-over from hot to cold. Some valves designs are more likely to enable this than others. If you turn the faucet's handle all the way to one side or the other, you may stop the cross-over. Shutting off the angle stops at the wall one at a time should help isolate which one is doing it, then, repair or replace that faucet.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  8. #8
    George the Plumber Gsalet's Avatar
    Join Date
    Sep 2010
    Location
    San Francisco
    Posts
    83

    Default

    Depending on the model of faucet you may have a bad check valve. Pressure balance valves using a separate balance spool like grohe, wolverine have check stops that can cause havoc when dirt prevents them from fully closing.

Similar Threads

  1. cold water pressure in faucet slower than hot water!
    By m3gtr in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 3
    Last Post: 09-17-2009, 11:50 AM
  2. Pressure Balancing Valve Output
    By bbradski in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 1
    Last Post: 06-15-2009, 07:53 PM
  3. Pressure balancing valve stuck
    By zone29 in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 3
    Last Post: 09-19-2008, 06:34 AM
  4. Trouble with pressure balancing valve
    By jasdyer in forum Shower & bathtub Forum & Blog
    Replies: 4
    Last Post: 05-04-2008, 08:14 PM
  5. Pressure balancing valve problem
    By Bill_R in forum Shower & bathtub Forum & Blog
    Replies: 4
    Last Post: 02-25-2006, 01:41 PM

Bookmarks

Posting Permissions

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