Hot Water Tank doesn't hold water ?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by lhartl, Jun 24, 2007.

  1. lhartl

    lhartl New Member

    Hello,

    We have a hot water tank that is not producing hot water. When I went to drain it, I realized that its not holding any water - about six cups of water emptied from the tank. So I tried to refill it and it just stops filling after about 10 seconds and about 6 cups of water are in the tank.

    I have tripped the pressure relief valve - not sure how to test it other than lift it and let the water run out.

    Any suggestions on what might be causing this problem? We are at the lake and of course, no plumbers for 150 kilometeres!

    thanks,
    Linda
  2. Cass

    Cass Plumber

    Messages:
    5,980
    Location:
    Ohio
    If you push on the tank does it rock?

    Some times the drain valve will clog and not let much water out.

    How old is the unit?
  3. lhartl

    lhartl New Member

    thanks for the response,

    the unit is five years old. It does not rock. The drain is on the lower side of the unit and so I can see that it is running freely.
    Is there another drain on the bottom of the unit?
    When I try to refill it, the water stops filling after about 6 cups of water. any other ideas?
  4. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,560
    Location:
    North Carolina
    Open a hot water valve somewhere in the house and see if this helps
  5. lhartl

    lhartl New Member

    Hi again,

    When I turn on the hot water tap, the water runs through just fine - except its not hot! Is there something inside that tells it when to stop filling up with water that may be wonky?

    thanks for the reply!
    Linda
  6. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,560
    Location:
    North Carolina
    Open a hot water valve somewhere in the house and see if this helps. If there is no air to replace the water the tank will pull a vacuum and the water will stop flowing. By opening a hot water valve air is allowed to replace the water that is leaving the tank and it should empty completely.
  7. Cass

    Cass Plumber

    Messages:
    5,980
    Location:
    Ohio
    At this point, I would think that, you need to call a plumber to fix the heater.

    Why is it that you want to drain the heater?
  8. lhartl

    lhartl New Member

    Hi again,

    I have a plumber coming this evening.

    The only reason I was trying to drain it was to see if there was sediment in the tank that may have caused the tank to not produce hot water.

    that's when I realized that it wasn't holding any water in the tank!

    the plumber that I talked to earlier on the phone thinks that maybe a burned out element is causing the problem, we'll see tonight.

    cheers,
    linda
  9. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,274
    Location:
    New England
    If for some reason the tank wasn't full and the thermostat turned on, you certainly burned out one or both of the elements. The bigger question is why was it empty.
  10. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,062
    Location:
    Cave Creek, Arizona
    heater

    Your tank is not empty. Without a way for air to enter the tank the water cannot drain out. But that is not the reason the tank is not heating. You have an electrical problem which could be a bad element, or elements, or it could be something else altogether.
  11. GrumpyPlumber

    GrumpyPlumber Licensed Grump

    Messages:
    1,404
    Location:
    Licensed Grump
    On electric water heaters you can put your ear to the panel where each element is (upper & lower) while it's on...you should hear a light humming sound, otherwise it's a bad element (so my wife says of me).
  12. Verdeboy

    Verdeboy In the Trades

    Messages:
    2,051
    If you have good water pressure when you open a hot water tap, then the tank must be full. Notice in the diagram that the cold water must go to the bottom via the "dip tube" which forces the hot water to leave out the top.

    One unlikely scenario is that your dip tube is broken, and the incoming cold water goes straight out the outlet because the rest of the tank is full of crud.

    Attached Files:

    Last edited: Jun 25, 2007
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