Ruud40 gallon Gas Hot Water Heater

Discussion in 'Water Heater Forum, Tanks' started by jarge40, Feb 12, 2012.

  1. jarge40

    jarge40 New Member

    Messages:
    1
    Location:
    pa
    Have a Ruud 40 gallon Gas Hot Water Heater that was installed 9/28/2008. Unit is still under warrenty (tank and component parts - both 6 year warrenty).
    For the past month (no previous problems), have been running out of hot water prematurally. Tried setting temp. to highest setting, still no change. Checked water temp. after letting tank reach temp., was initially 140 degrees. After a 10 minute shower, had to turn off cold water completely. This has been occuring for the past month.
    Gas pressure in house is ok.
  2. Hackney plumbing

    Hackney plumbing Homeowner

    Messages:
    1,174
    Location:
    Alabama
    1) Whats the temp of your incoming cold water?

    2) Whats the temp of the water your showering with?

    3) How many gallons per minute comes out of your showerhead while your showering?

    Use a 5 gal bucket to see how many gallons per minute your showerhead flows.

    Give me that info and I will tell you if the heater is operating within its limits. If not then we will go into the possible problems.
  3. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,274
    Location:
    Land of Cheese
    If the heater is firing properly, it is very likely that the dip tube in the tank has failed. The dip tube directs the incoming cold water to the bottom of the tank.

    An unobtrusive way to prove it-
    If the dip tube has failed, your shower water will go cool, but if you take a sample out of the tank drain, it will be hot.
  4. Hackney plumbing

    Hackney plumbing Homeowner

    Messages:
    1,174
    Location:
    Alabama
    Your water heater should be able to deliver 70% of its tank volume within 20 degrees of the thermostat setting. For you this would mean the water heater should be able to deliver 28 gallons of water at a temp between 140 and 120 degrees.
  5. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,395
    Location:
    Yakima WA
    This certainly sounds like a dip tube failure. This was a big problem several years ago when a major supplier of dip tubes turned out faulty ones to a number of heater manufactures. While this problem has been rectified, it is still possible of a a dip tube to break. It is fairly easy to check and replace if necessary. The tube is flared on the the top end and just hangs in the cold water intake. Just remove the intake nipple and use your pinky finger to fish the tube out. If it is intact, it will be long enough to reach the bottom of the tank. If it's broke, just get a new one. You may need to trim the bottom end if it is too long. That's about all there is to checking and replacing a dip tube. Cheap too.
  6. Hackney plumbing

    Hackney plumbing Homeowner

    Messages:
    1,174
    Location:
    Alabama
    Dip tubes do not reach the bottom of the tank. Manufacturers have shortened the dip tubes lenght to HELP against thermal stacking.

    The best way to check a water heaters function is to perform a draw test. The heater should deliver 70% of its tank volume(in this case 28 gal) within 20 degrees of its thermostsat setting. In this case his water is 140 degrees so it should deliver 28 gal of water between 140-120 degrees.

    After the draw test if the heater fails then is the time to trouble shoot hands on.
  7. slab home or crawl space??

    if you live on a slab home, odds are you might have a hot
    water slab leak.....

    this can resemble a dip tube problem...

    you can watch your meter to see if water is passing
    through the pipes....
  8. Hackney plumbing

    Hackney plumbing Homeowner

    Messages:
    1,174
    Location:
    Alabama
    A quick way to check to see if theres a leak on the hot side that matters is to turn the cold water off to the heater. wait a few minutes and then turn it back on. If there is a leak you will hear the heater pressure up.
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