hot and cold water

Discussion in 'General Plumbing Help' started by davedeee68, Jan 20, 2020.

Help Support Plumbing Forums by donating:

Tags:
  1. Jan 20, 2020 #1

    davedeee68

    davedeee68

    davedeee68

    New Member

    Joined:
    Jan 20, 2020
    Messages:
    3
    Likes Received:
    0
    Hi
    I am having trouble with running a constant and even temperature from my bath taps. We have mixer taps (not that I think these are at fault). When running the water from the shower head (don't have separate shower, just hose connected to taps), the temperature is ok, then suddenly it goes scolding hot, then cool, then hot, then cold etc etc........

    Is it anything to do with the boiler, the taps, or is it the valve (brass inner that has washer on that fits into tap)?

    Just can't get an even flow of temperature. When my wife washes her hair, she is fine for a while, then yelps out as it is much too hot, then shouts again as it is too cold, and so on.......

    What is the problem please?
     
  2. Jan 20, 2020 #2

    Jeff Handy

    Jeff Handy

    Jeff Handy

    Pro Handyman, NOT A Pro Plumber

    Joined:
    Jul 5, 2019
    Messages:
    1,294
    Likes Received:
    219
    Location:
    Chicago suburbs
    This is usually caused by someone else using water elsewhere in the house.

    So someone flushes a toilet, using cold water, and she gets suddenly more hot shower water.

    Someone washes their hands with warm water, or dishwasher or washing machine are using warm water, and she suddenly gets mostly cold water at the shower.

    And/or your bath valves might need new cartridges.
     
  3. Jan 20, 2020 #3

    davedeee68

    davedeee68

    davedeee68

    New Member

    Joined:
    Jan 20, 2020
    Messages:
    3
    Likes Received:
    0
    Hi Jeff

    Thank you for your reply. We make sure that we do not use any other taps while running water from bath/shower attachment, so must be 'new valves' needed. Thank you for taking time to answer, it has been very helpful.
     
  4. Jan 20, 2020 #4

    Jeff Handy

    Jeff Handy

    Jeff Handy

    Pro Handyman, NOT A Pro Plumber

    Joined:
    Jul 5, 2019
    Messages:
    1,294
    Likes Received:
    219
    Location:
    Chicago suburbs
    Might not need new valves, just get new guts or cartridges for the valves you already have.

    However, if you DO get all new valves, you should get pressure balanced valves.
    Also called anti-scald valves.

    They will automatically adjust hot and cold internally, so the shower won’t suddenly change temperature.

    You might already have these, and maybe they just need new parts inside.
     
    Last edited: Jan 20, 2020
  5. Jan 20, 2020 #5

    Jeff Handy

    Jeff Handy

    Jeff Handy

    Pro Handyman, NOT A Pro Plumber

    Joined:
    Jul 5, 2019
    Messages:
    1,294
    Likes Received:
    219
    Location:
    Chicago suburbs
    And even if you think you are not running any other water during a shower, it might be happening anyway.

    For example, if your furnace has a humidifier, that will use water when it comes on.

    Toilets often leak and will refill by themselves.

    Your ice maker in the fridge will use water as needed, automatically.
     
  6. Jan 20, 2020 #6

    Geofd

    Geofd

    Geofd

    Moderator Staff Member Professional Supporting Member

    Joined:
    Jan 20, 2018
    Messages:
    1,606
    Likes Received:
    238
    Location:
    Boston, Massachusetts
    Is this problem only with your shower/tub valve or is it everywere?
     
  7. Jan 21, 2020 #7

    Mitchell-DIY-Guy

    Mitchell-DIY-Guy

    Mitchell-DIY-Guy

    Well-Known Member

    Joined:
    Oct 16, 2019
    Messages:
    60
    Likes Received:
    18
    Location:
    Philadelphia
    It's possible that its just bad plumbing design.

    Speaking generally in terms of copper pipe, a main feed should be 3/4", and branch lines that feed fixtures are 1/2", in most cases. I've seen some really stupid plumbing where 1/2" is used throughout, typically a cost-saving measure without thought to the consequences for the owner and user...like my daughter's rental row house where the cold water lines are 3/4" but the hot water out of the hot water tank is 1/2"; what the heck were they thinking? Of course her shower sucks, especially when someone else is washing dishes and a load of laundry is being done. Seriously!

    If you have the former, there is or should be, enough pressure and volume in the 3/4" main feed to serve a number of 1/2" branches, such as faucets and showers and toilets. If you have only 1/2", then there will possibly be issues.

    Speaking of bad plumbing design, the first house I owned had a full 360 degree loop for cold water that went all the way around the basement, with 1" galvanized. Some of that was so corroded on the inside I quickly realized there's no fixing stupid; I ripped it ALL out and used proper 3/4" main lines and 1/2" branch lines all in copper. On that same house, we eventually added a bathroom upstairs and I remember working with the plumber as he ran 3/4" lines up a pipe chase. I questioned his use of 3/4" and he said, "you want a good shower right? we use 3/4 to get there and 1/2 to tee off to the fixtures...any questions?"

    To see if this piping issue may be a cause for you, you'll need to see if you can trace the lines down from the shower back to the hot water tank, and ditto for the cold water, and see if you have any mismatches.

    As for the "balance valves" for showers, there are two kinds out there; pressure balance, and thermostatic balance. One reacts to just changes in pressure, the other to changes in temperature. Read this for a bit more information:

    https://www.plumbingsupply.com/pressure-balance-vs-thermostatic-valves.html
     
  8. Jan 21, 2020 #8

    davedeee68

    davedeee68

    davedeee68

    New Member

    Joined:
    Jan 20, 2020
    Messages:
    3
    Likes Received:
    0
    Hi

    Apart from using sink to have a wash in bathroom, or sink downstairs for washing up, we do not use much water, and while using the sinks, have no need to run the water for too long, so would say that it is just the bath/shower taps.
     
  9. Jan 21, 2020 #9

    Geofd

    Geofd

    Geofd

    Moderator Staff Member Professional Supporting Member

    Joined:
    Jan 20, 2018
    Messages:
    1,606
    Likes Received:
    238
    Location:
    Boston, Massachusetts
    Is this a new problem or did it judt occur if its always been there some shower valve brands make stems for a tankless application and another for a hot water tank if its just now happening and and effecting more than one fixture if you are heating with a boiler you may want to clean yourtankless mixing valve stem vinagar works well you can also do this to your shower valve stem/cartridge
     
  10. Jan 21, 2020 #10

    Geofd

    Geofd

    Geofd

    Moderator Staff Member Professional Supporting Member

    Joined:
    Jan 20, 2018
    Messages:
    1,606
    Likes Received:
    238
    Location:
    Boston, Massachusetts
    Is this a new problem or did it judt occur if its always been there some shower valve brands make stems for a tankless application and another for a hot water tank if its just now happening and and effecting more than one fixture if you are heating with a boiler you may want to clean yourtankless mixing valve stem vinagar works well you can also do this to your shower valve stem/cartridge
     
  11. Jan 21, 2020 #11

    Jeff Handy

    Jeff Handy

    Jeff Handy

    Pro Handyman, NOT A Pro Plumber

    Joined:
    Jul 5, 2019
    Messages:
    1,294
    Likes Received:
    219
    Location:
    Chicago suburbs
    Geofd.

    Periods, commas, and paragraphs would make your good information more readable.

    Just my opinion, feel free to ignore.
     
  12. Jan 22, 2020 #12

    Geofd

    Geofd

    Geofd

    Moderator Staff Member Professional Supporting Member

    Joined:
    Jan 20, 2018
    Messages:
    1,606
    Likes Received:
    238
    Location:
    Boston, Massachusetts
    i won't ignore!!!!!
     
  13. Jan 22, 2020 #13

    Jeff Handy

    Jeff Handy

    Jeff Handy

    Pro Handyman, NOT A Pro Plumber

    Joined:
    Jul 5, 2019
    Messages:
    1,294
    Likes Received:
    219
    Location:
    Chicago suburbs
  14. Jan 22, 2020 #14

    Diehard

    Diehard

    Diehard

    Well-Known Member

    Joined:
    Aug 19, 2017
    Messages:
    2,368
    Likes Received:
    409
    Location:
    North Reading, Mass.
    As Geofd touched upon, what exactly is your domestic hot water source?

    If it is a tankless boiler with heater exchanger for domestic hot water, which typically tries to control the hot water temp coming out of the boiler with the required tempering valve and trying to do it during the heating months, a good chance a part of your problem is that the tempering valve on a boiler doesn't control the average boiler water temperatures that ranges from say 160 F up to 180 to 200 F, based on whether it's calling for heat or not. Particularly as they age.

    Then of course as Mitchell-DIY-Guy states, just bad plumbing design with regard to piping sizing.

    The third consideration, pressure balance, and thermostatic balancing valves?
    All I can offer is a suggestion to try to test if you get any of these sudden changes of temperature when using non-pressure balance and thermostatic balancing valves.

    Also, make more of an effort to find out what's taking place elsewhere during these sudden flucuations. In other words, go so far as to try to cause them.
     

Draft saved Draft deleted

Share This Page

Group Builder