Water Heater Cold Water Inlet "Overflow"

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by Rod, Dec 27, 2008.

  1. Rod

    Rod New Member

    Messages:
    17
    Location: Spring Lake, NC

    Water Heater: Electric, Bradford White

    Model #: M250S6DS2

    Concern: Cold Water Inlet "Overflow" Is Active

    *SEE PHOTOS

    Hello, my name is Rod. Thank you for taking the time to assist me. Please forgive my ignorance of water heater know-how. This is precisely why I request your assistance. (smile) Firstly, I do not know if what I refer to as the "overflow" is indeed an overflow. But, it is definitely attached to the cold water inlet. I recently had my water heater wrapped and noticed some water underneath it yesterday. Not a lot of standing water, but enough to tap your finger against it and make a small 'splash'. You can see in the photo the area beneath the drain valve I had wiped dry. I unwrapped the unit and proceeded to trouble shoot- the drain valve was dry, as well as the TPRV discharge tube. But I did notice moisture coming from a 1/2" PVC tube connected to the cold water inlet.

    This is what I refer to as an overflow, if that is correct. I wiped the area dry and directed the PVC tube into a bucket. I checked the bucket 24 hours later (today), and it had about an inch of water in it. The area around the base of my water heater was dry. So, the water heater itself is not leaking.
    Of course, the water came from the PVC tube attached to the cold water inlet.

    If this is an overflow, please enlighten me on how it is activated, and how often this should occur.

    If it is not an overflow PVC tube, please educate me on its purpose along with anything I should be concerned about.

    Thank you for your time.
    -Rod



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  2. Probedude

    Probedude New Member

    Messages:
    137
    Location:
    CA
    Remove the insulation where that pvc pipe attaches so we can have a better look.

    - it's not an overflow but maybe there's a valve under there for an ice maker or RO unit that is no longer installed.
  3. Rod

    Rod New Member

    Messages:
    17
    What's an RO unit do?

    Hopefully these will help for you to explain my problem. BTW, I purchased my home new in 2005. There have not been any mods to the unit since then.

    This tube should not be leaking, huh? A course of action is appreciated.

    Thank you!
    -Rod

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  4. SewerRatz

    SewerRatz Illinois Licensed Plumber

    Messages:
    1,705
    Location:
    Chicago, IL
    ok I have to say this is the first time I seen a valve like that. At first I was thinking it was a stop and waste. But if it where a waste drain off wouldn't water come out of that constantly like full flow. I hope the other guys can enlighten this young Chicago boy on that valve.
  5. Rod

    Rod New Member

    Messages:
    17
    I never paid much attention to it before. But upon closer examination I thought it was odd too. Especially since I was thinking it was an overflow.
    But then I thought, "Why would there be an overflow on the cold water inlet?". But of course, I'm not up on water heaters so I brought my question here.

    Now I'm wondering... did the plumber do a sloppy job by using the wrong cold water shut-off valve.? One that has an extra valve, and he decided to run a PVC pipe from it?

    Then my next question would be, "Why didn't the inspector catch this?".

    Perhaps I'm jumping to conclusions...
  6. Verdeboy

    Verdeboy In the Trades

    Messages:
    2,051
    My only guess is that the mystery line goes to a non-existent expansion tank.

    Attached Files:

  7. Rod

    Rod New Member

    Messages:
    17
    BTW, I did run my shower HOT to see if any water would drain from the PVC and into the bucket once cold water came in to replace the outgoing hot.

    Nothing happend while the shower was running. Nor did anything happen within 5 minutes of shutting the shower off.

    But when I checked it about an hour later, there was a little water in the bucket.

    So, how long does it take for cold water to replace outgoing hot? How long before the cold water flows into the water heater?

    This is what I was trying to figure out while I was trouble shooting it.
  8. SewerRatz

    SewerRatz Illinois Licensed Plumber

    Messages:
    1,705
    Location:
    Chicago, IL
    See what happens when you turn off the ball valve. I am just curious.
  9. Verdeboy

    Verdeboy In the Trades

    Messages:
    2,051
    Cold water fills the tank instantly, as hot water is used.
    Good idea, Ratz. I love experiments. :)
  10. Rod

    Rod New Member

    Messages:
    17
    If that's it then my valve is upside down, huh?:D
  11. Rod

    Rod New Member

    Messages:
    17
    BTW, if it is for an expansion tank shouldn't the plumber have 'capped off' the valve since there is no tank?
  12. SewerRatz

    SewerRatz Illinois Licensed Plumber

    Messages:
    1,705
    Location:
    Chicago, IL
    If it where for a tank, water should be flowing out of it nonstop. Otherwise it is useless.
  13. Verdeboy

    Verdeboy In the Trades

    Messages:
    2,051
    It also means the installer never came back from that long lunch to finish the job. But that's only a guess. That valve may be for something else.
  14. Rod

    Rod New Member

    Messages:
    17
    I turned off the cold water inlet (if that's what you meant) and nothing happened.

    The tube definitely expells water when hot water is used. It seems like about an inch or so a day in my bucket. I hate the thought of wasting that water. That can add up over time.
  15. Rod

    Rod New Member

    Messages:
    17
    Hummm... what other purpose could it serve?
  16. Verdeboy

    Verdeboy In the Trades

    Messages:
    2,051
    In my research, the only 3-way ball valve I could find with a plastic tube coming down is for winterizing hot water tanks in RV's. The tube somehow sucks antifreeze into the tank from a bucket. But my guess is, you don't live in an RV. :)
  17. WTF is going on in here?!?!?!?!


    That's a Watts Thermal expansion Ball Valve Shutoff.


    It's dumps water when thermal expansion is present, or is malfunctioning which could easily be the case.



    Hard pipe copper out of that tank on the cold side, tee off and install a thermal expansion tank and get rid of that valve, install a normal ball valve.


    Then reconnect back to that PEX.

    Before you do any of this, check your static water pressure at a hose bibb and determine what the pressure is incoming.


    If it is above 60, near 80, you got other problems as well.

    An expansion tank will provide protection to as little as 1/2 pound of deflection on the bladder, that cannot be achieved with that valve, which is not good at all for the life and longevity of your plumbing system.
  18. MACPLUMB 777

    MACPLUMB 777 TROJAN WORLDWIDE SALES RP

    Messages:
    679
    Location:
    Houston, Texas, United States
    Water heater

    Just what rugged said,
    this is a thermal expansion valve
    have a plumber replace with a thermal expansion tank
  19. nhmaster

    nhmaster Master Plumber

    Messages:
    3,189
    Location:
    S. Maine
    My only guess is that the installer was too cheap to install a ST5 expansion tank and use an expansion valve instead. I think I would remove the valve and install a standard ball valve along with a 3/4" female tee and an expansion tank instead.
  20. Cass

    Cass Plumber

    Messages:
    5,979
    Location:
    Ohio
    It will look something like this only it will be supported...this one is not...a simple strap would work...

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