Is this symptomatic of a potential problem?

Discussion in 'Water Heater Forum, Tanks' started by davidyal, Feb 23, 2009.

  1. davidyal

    davidyal New Member

    Messages:
    2
    We have a 60 gallon gas water heater that serves our upstairs bathroom. Hot water was working great this morning. Several hours (~10) later this evening, we ran the hot water but only luke warm water came out and nothing hot. I examined the tank in the attic and the it appeared to be working with no signs of leaking. I did notice thoiigh that the cold water input line was actually quite warm, and almost as hot as the hot water output line.

    An hour later, I opened the hot water faucet again and suddlenly hot water was flowing normally. Strange, considering I didn't make any adjustments to the tank.

    Should I be concenred about:
    1. Why was the hot water not flowing when I tried in early eveing?
    2. The cold water line coming into the tank was warm (almost as hot as the hoit water output line)

    Any tips on how to troubleshoot would be appreicated.

    David
  2. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,396
    Location:
    Yakima WA
    Many water heater in the mid 90s had faulty dip tubes. This occurred with many brands because the producer of the dip tubes sold the tubes to many companies. As you may already know, cold water comes in at the top of the tank, goes into the dip tube which carries the water to the bottom of the tank. If the dip tube breaks off, the cold water does not go to the bottom of the tank so the lower part of the tank has only cold or at best warm water. Checking and replacing the dip tube is quite simple. Turn off the water, the disconnect the intake line from the tank. Remove the nipple that is threaded into the top of the tank. The dip tube simple hangs by it's flanged end in the opening directly under the nipple. You can use use your finder to fish the tube out. It should be long enough to go clear to the bottom of the tank. If it has broken, you can get a new tube at any plumber shop or hardware. It it is too long, just cut the end off. Replace the nipple and reconnect the water line and turn the water back on. It is not necessary to drain the tank to do this, but if you do, be sure you do not turn the gas back on until the tank is purged of air.
  3. Cass

    Cass Plumber

    Messages:
    5,980
    Location:
    Ohio
    Please post the Make, Model # and Serial # of the unit and we can tell you more...is your water hard...
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    22,321
    Location:
    New England
    When water isn't actually flowing, conduction will warm the incoming line. They usually install a device to limit that, but it is connected and metal (in many cases), so it will conduct. Probably not anything to worry about.
  5. davidyal

    davidyal New Member

    Messages:
    2
    Thank you for all the great information. I guess what puzzles me most is why last night there was no hot water flowing from the tap, and then 2 hours later it seemed to be working again.

    Cass: here is the model info. I suspect it is about 8 years old.
    Bradford White. Model MI5036EN10. Serial WA8326937. 50 Gallon. 40,000 BTU

    I'd like to share a picture of the current setup. There is a weird design from the previous owner, and I'm hoping this forum may help determine if I need to make changes.

    There are 2 identical 50 gal tanks that were installed in parallel. These both serve the master bathroom. (There is a 3rd 75 gal tank for the rest of the house)



    The previous owner decided that 2 heaters were not necessary, and installed valves on the cold water line of each tank. One tank has been constantly turned off and it's cold water line shut.

    1. Is this design acceptable? I'm concerned that because only the cold water valve is shut on the tank not in use, water may enter via the hot water connection. DO I need to install a valve on the hot water connection of the non-used tank as well?

    2. On the main hot water return (i.e. the pipe that is fed by the hot water output of each tank) there is a ball valve that appears to have developed some rust. It looks like that valve can only open to 45 degrees since it is blocked by the other pipes. Should this be changed so the valve can open the full 90?

    3. It consistently takes 2-3 minutes for hot water to flow from the taps. Usually it is cold/luke warm water until the hot begins. Could this design be affecting this? I once asked a plumber who was in the house and he said "can't do anything..it’s the way the house was plumbed"

    I realize this is a lot of info...but I've had plumbing on my mind and waht to be informed before I hire someone to change pipes or do the simpler work myself.

    Attached Files:

  6. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,321
    Location:
    New England
    Keep in mind...I'm not a pro.

    1. I'd consider a valve on the outlet. I'd want to drain the tank...letting the water sit in there stagnent could be a problem but it should not affect heat output from the other tank.

    2. I'd change and reposition the valve. Ball valves aren't good as volume controls, but not being fully opened could restrict the flow.

    3. How far does the pipe have to go before it gets to the bathroom? You might be a good candidate for a hot water recirculation system. How long it takes to get hot water would depend on how or if the pipes are insulated, how large they are, and how long they are. Note, some shower control valves (and some vanity faucets) are known to sometimes create a cross-over between hot and cold, which can limit and slow how fast you get hot.
  7. Scuba_Dave

    Scuba_Dave Extreme DIY Homeowner

    Messages:
    885
    Location:
    South of Boston, MA
    Does the hot water of both tanks combine into 1 output?

    If the cold input is shut off to the 2nd tank I can't see any measurable amount of water entering or exiting since it is a "dead" end

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