Warm water from cold tap in kitchen

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by MrTerrible, Jan 14, 2019.

  1. MrTerrible

    MrTerrible New Member

    Joined:
    Jan 14, 2019
    Location:
    markham, ON
    I'm trying to help my mother diagnose her issue. About 6 months ago, my mother started to find that when she turns on the cold water tap in the kitchen, the water starts off luke warm, gets warner, then gets cold. Other taps in the house don't have this problem.

    Unfortunately, she doesn't have individual shut-off valves for the kitchen sink so I have to turn off the main water valve if I have to tinker with the faucet. She had the water tank replaced (it was around 15 years old) but that didn't help anything. She also had a new faucet installed in the kitchen by a plumber. The problem still persists. I touched the hot and cold water pipes (they are copper) that connect to the faucet. The cold water pipe is cold, and the hot water pipe is warm (it will be hot if I run the hot water).

    I was reading that there may be cross-over and that common places to look are show/tubs. Her shower is not directly above the sink, but is on the floor above and maybe 20ft away. I changed the cartridge to the shower, but that didn't do anything either. She has a bath tub (which is not used), and we have one more shower that is located at the other end of the house on the 2nd floor.

    Does anyone have any suggestions on what else to try, or does she just live with it? What is odd is that it only started happening about 6 months ago, so I don't think this is specifically a piping issue as the pipes haven't changed in 25 years.


    Grant
     
  2. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Could it be that the kitchen cold pipe runs along the heating duct, and that heats the pipe? I understand that 6 months ago was not the heating season, but maybe the time estimate is off some.
     
    Last edited: Jan 14, 2019
  3. Sponsor

    Sponsor Paid Advertisement

     
  4. themp

    themp Member

    Joined:
    Feb 5, 2008
    Location:
    Raleigh, North Carolina
  5. MrTerrible

    MrTerrible New Member

    Joined:
    Jan 14, 2019
    Location:
    markham, ON
    Hi themp,

    Since the water tank is new, I'll assume I can shut off the water to the water tank. I know in my house, the shutoff valve is before the water splits into the tank and mixing valve. I'll have to check her setup when I go there on the weekend. From what I remember, she doesn't have a mixing valve at the water tank. When they replaced the tank a month ago, they installed new shut-off valves so that shouldn't be a problem.

    I read the article you mentioned. Since my problem is with the warm water coming through the cold water tap (opposite of what the article is addressing), I should close off the hot water valve from the tank and turn on the cold water on the kitchen faucet. If warm water comes out, that means that the hot water valve near the tank is defective and is allowing hot water to still run and the crossover is occurring elsewhere, or something may be heating the cold water pipe (though my parents haven't done any renovation since the house was bought 25 years ago). Is this correct? I'll have to check how warm/cold the pipe feels when I run the cold water tap in the kitchen.

    Let's assume that the water is still cold after turning off the hot water valve at the water tank. So what I should do now is shut off the water to all faucets that use the single handle and check to see if the water is cold. Hmm...not all my faucets have their own water shut-off valve. I'll try shutting off the faucets that I can to see if the problem still occurs. If it does, that means it could be one of the faucets that I can't shut off individually. I guess if it come down to that, I'll have to try replacing the cartridges on the other shower, and bathroom sinks. Good thing they are Moen faucets so I can get free cartridges.
     
  6. themp

    themp Member

    Joined:
    Feb 5, 2008
    Location:
    Raleigh, North Carolina
    Here is a more simpler approach that was posted on this thread:

    https://terrylove.com/forums/index.php?threads/crossover-between-hot-and-cold.6145/

    hj said:

    "I run into "bad" Moen cartridges that are "crossing over" all the time. One way to find them is to turn off the water heater supply then open a sink's hot water faucet. If water still flows you have crosssover. Then go to each Moen, Mixet, Grohe, etc., and turn it to the full hot side. Unless there is more than one bad one, when you turn the bad one, the water flow will stop. You can also sometimes hear the water crossing over inside the valve if it is bad enough. One thing to remember, is that the bad cartridge may not be, and often is not, in the apartment having the problem."

    The key above is that you open the hot on a sink that has two knobs. Then when you go around and turn on the single handle faucets to hot, the hot on the sink with two knobs will stop.
     
  7. MrTerrible

    MrTerrible New Member

    Joined:
    Jan 14, 2019
    Location:
    markham, ON
    Ok cool. I'll do that over the weekend when I drop by her place. Thanks for your help.
     
  8. wjcandee

    wjcandee Wise One

    Joined:
    Apr 27, 2012
    Location:
    New York, NY
    That's also exactly the symptom of what happens if you have one of those hot-water trickle-recirculation-to-cold installations, the poor man's version of a full hot-water recirc system. We have one in our house. At the faucet at the end of the line, the thing is installed. So, at the sink closest to that installation, when it's cold out and the crossover valve opens, the closest sink has exactly that symptom. And everyone gets hot-ish water from the hot tap almost immediately even though it's 20 degrees outside and there's a 200-foot run from the boiler.
     
  9. MrTerrible

    MrTerrible New Member

    Joined:
    Jan 14, 2019
    Location:
    markham, ON
    I dropped by my mom's place today (for other reasons, but I thought I would give it a try). I turned off the water to the water tank. I went to the laundry room and turned on the hot water. Some water came out but eventually it stopped. I left the tap open. I then went to each single handle faucet (except the bath tub) and turned on only the hot water. They all had no water flowing from the tap, EXCEPT the basement bathroom sink. Water kept flowing out when I turned the handle to hot water. Luckily, this sink had water shut-off valves going to the sink so I shut off both hot and cold water. I turned the water back on to the water tank. I then went back to the kitchen sink and cold water flowed from the cold tap. I told my mom to check it in the morning (where she notices the problem the most). If the water is cold from the cold water tap (hopefully), then it looks like I have found the cause of the cross-over and will have to get a new cartridge. I'm not sure if it is a Moen faucet as I don't see any branding so I'll have to take it apart and see what it is.

    Thanks for everyone's help. Will update once I get an update from my mom.
     
  10. MrTerrible

    MrTerrible New Member

    Joined:
    Jan 14, 2019
    Location:
    markham, ON
    Hmm...that didn't help. I called my mom this morning and she used the upstairs bathroom (just the cold water tap). She went downstairs to the kitchen, and the faucet spout was warm without turning on the tap. Of course when she did turn on the tap, the water was warm, but eventually went cold. The basement sink still has the valves shut-off so something else is happening :(
     
  11. themp

    themp Member

    Joined:
    Feb 5, 2008
    Location:
    Raleigh, North Carolina
    I assume the bathtub is two handle and not single? Make sure you test all single faucets when the water is turned off to the water heater. And if any single faucet has shutoffs you could start shutting them off like you did for the basement and tackle this by elimination. Also, have you turned off the supply to the washing machine?
     
  12. MrTerrible

    MrTerrible New Member

    Joined:
    Jan 14, 2019
    Location:
    markham, ON
    I believe the bathtub in the Master bedroom is dual handle, but the other bathtub on the second floor is single handle. I forgot to check that one. I did not turn off the water supply to the washing machine. I'll try to get to those two over the weekend.
     
Similar Threads: Warm water
Forum Title Date
Plumbing Forum, Professional & DIY Advice Help with Hot water heater, luke warm and no pressure. Sep 6, 2019
Plumbing Forum, Professional & DIY Advice Cold water is warm. Aug 15, 2019
Plumbing Forum, Professional & DIY Advice How to make a warm floor using a hot water pipe? May 15, 2019
Plumbing Forum, Professional & DIY Advice Electric water heater Luke warm mornings Feb 11, 2019
Plumbing Forum, Professional & DIY Advice New Delta Shower - Not hot water Lukewarm only Nov 19, 2018

Share This Page