Hot Water tank - Electric

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by lybush, Jan 5, 2005.

  1. lybush

    lybush New Member

    Messages:
    5
    We have an electric 40 gal. hot water tank in our garage and I believe something could be wrong with it. In the mornings, the water temp. seems a lot cooler than usual. This has been going on for quite a while and is not due to the colder water in the winter. We have two elements: 2500 watts upper and 2000 watts lower. Total says 2500 so I assume only one heat element is active at a time.

    I want to check the thermostats and heater elements but don't know the correct procedure. If I need to change either one, MUST the water be drained from the tank first???? I don't want to unscrew anything and find water all over the place.

    Thanks all for any information that you may offer.

    Len
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,143
    Location:
    New England
    YOu could have deposits in the tank that insulate the elements. COuld be lots of things. FIrst, try draining some water out and see ifyou get gunk. How old is it?
  3. jrejre

    jrejre New Member

    Messages:
    61
    Location:
    Minnesota
    I am not a professional plumber, but have done this several times myself. The steps I would take are:

    1) Turn off the electrical power at the circuit breaker panel - MAKE SURE IT"S OFF!

    2) Turn off the supply water to the water heater.

    3) Drain the tank - I use a hose connected to the bottom drain valve

    4) Take off the covers to the access panels for the heating elements. These usually come off with 1 or 2 screws. There's usually 1 about 1/3 the way up and 2/3 the way up.

    5) Usually there is a small insulation pad or insert that has to be pulled out in order to get to each heating element.

    6) Disconnect the wires to the heating elements. Usually you just have to loosen 2 screws for each element.

    7) Get a water heater heating element wrench - not very expensive and available at every hardware store that I'm been to.

    8) Take out each heating element. Often failure is apparent. Replace 1 or both heating elements. Depending upon your appetite for $$, I usually just replace both of them. I think of them kind of like light bulbs. If one goes, the other one will probably go soon. Just my opinion.

    9) Screw back in the new element(s), reconnect the wires, reinstall any insulation cover, screw back on the metal access cover.

    10) Turn on the water and allow the water heater a good 30 minutes to fill. If you turn on the power before both elements are in water, you'll burn out the heating element that's not in water. Better to allow ample time to fill.

    11) Go around and turn on a faucet or to to bleed out air.

    12) Once you are pretty certain it's full of water, turn back on the circuit breaker.

    That should do it.
  4. Deb

    Deb Plumber

    Messages:
    200
    Location:
    Idaho
    Deb

    Jadnashua has asked you the most important question: How old is the tank?
    Also, did ANYTHING else, even if you think that it is not related, happen when this seemed to start?
    Do you drain and flush the tank regularly? Deposits can and do encrust the lower element making it less effective, which could conceivably allow the water in the bottom of the tank to cool slightly, if hot water had not been used for a long period, like overnight. However, hot rises and hot is pulled off the top of the tank, so this is not really an option.

    Before you get too carried away checking and/or changing elements and thermostats, lets try to figure out a little more. What you are telling us does not make logical sense, so we need to make some sense out of what is going on. Thermostats and/or elements will affect the heater all the time, not just in the morning. So, do not drain the tank and replace the elements (you can check these for continuity without draining the tank).

    First of all, check the actual temperature at different times of the day. Run the hot only from a two handle faucet when checking. Make sure that no other fixtures are being used.

    Cold water temperatures differences in winter and summer are not really significant (when dealing with hot water temps only, it does affect mixed temps like showers)--the water will heat to a preset temp, it will simply take a very short time longer. And water lines are buried below frost lines, so, unless you have a pressure tank in a colder location, the outside temp may have little to do with the water temp.

    Deb
    The Pipewench
  5. lybush

    lybush New Member

    Messages:
    5
    Thanks for all the useful informatiom.

    The tank is about 6 years old and we haven't done a think with it besides using the hot warm it produces.

    Nothing unusual happened. I just began to notice that in the mornings the water was not as warm as usual. So, I thought an element or thermostat might have gone out.

    I was just wondering how to proceed. I did turn up the thermostats from about 125 to 130 or so. On Mondays, when my wife washes clothes, she is now complaining that there is not enough hot water. She does that first thing in the morning.

    I didn't know you need a special wrench to remove the heaters. Looked like a
    regular curved head, I forget what you call them, wrench would do it. Looks like a nut that is used in electrical boxes to me.

    Len
  6. jrejre

    jrejre New Member

    Messages:
    61
    Location:
    Minnesota
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,143
    Location:
    New England
    Deb, while below the frost line, my incoming water temp near the end of last winter's worst cold spell was barely above freezing. This is in a condo with city water after it ran through the ceiling next the heat ducts about 100 feet! Normal summer water temps are around 55 degrees. That difference has made me go to a temperature controlled shower valve rather than just a pressure balance one, and I'm also discarding my problematic hybrid tankless system (soon - it's a problematic Trianco Heatmaker II - you've probably heard of them - good concept, bad execution). So, depending on where you live, winter incoming water temps can make a significant difference in the recovery and dilution of a hw tank. I will admit, that last winter was probably the coldest in a long time, but it does happen.
  8. Deb

    Deb Plumber

    Messages:
    200
    Location:
    Idaho
    Deb

    We discussed this on another forum. I have a large pressure tank located in an insulated room in my big (unheated) shop. The temp is kept not much above freezing. When taking a shower, this colder water has a twofold effect--not only do you need more hot to bring your shower to a comfortable temp, but the hot in the tank is cooled down faster because the incoming cold is colder. It makes quite a difference.
    However.....this is different. She believes that the hot water in the morning (all hot, not mixed with cold and no one else has used the water so the hot has not been tempered by incoming cold) is alot cooler than water during other times of the day. If no hot has been used, the temp of the hot water in the morning should be the the same as any other time that hot water has not been used for an hour or so--approx what the stat temp is.
    The only possible that I could come up with at all is: Maybe the pressure is building overnight, and sometime near morning, the T&P opens discharging excess pressure, cold water enters the tank, diluting the cold and....pretty remote to happen on any kind of regular timetable, though.
    Deb
    The Pipewench
  9. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,831
    Location:
    Cave Creek, Arizona
    water

    Your advice is good until you get to step #1. An experienced tester needs the power on to the heater to make the valid tests. Once that is done, if he finds a problem he turns off the power. Then he turns off the water. Then he removes the element(s), (only if he finds a bad one), and installs new elements without wasting an hour or more draining the tank. Finally he turns the water back on, then the electric power, and tests the heater for proper operation. But, if the electric wiring is done properly, he needs "bigger" elements than the ones in that heater to get a acceptable recovery rate.
  10. jrejre

    jrejre New Member

    Messages:
    61
    Location:
    Minnesota
    hj, I assume you're talking about my "#1". Your statement is not completely accurate. You can also test without power with a VOM. Both the elements can be tested with an ohm meter and so can the thermostats. We're splitting hairs here though. My suggestion to Len was assuming it would be safest for him not to try to test with power to the unit. If he's uncomfortable doing either, he should call a licensed, professional plumber.

    If you want to make it seem complicated for the average DIYer, that's ok too. Frankly, I am all for supporting my local plumber (both our family friends and my uncle are plumbers), but for a 6 year old heater, it's pretty cheap and easy for a DIYer to just change the elements. Frankly, I'd do it preventatively at that age. I'd also change the anode. Depending upon the specific heater, you can probably replace both elements and thermostats (the "throw all the parts at it approach") for under $75 including the wrench.

    But, that's just me.

    For what it's worth, if I had to guess on only 1 part, I'd put my bet on the lower heating element.
    Last edited: Jan 5, 2005
  11. Hube

    Hube New Member

    Messages:
    156
    Location:
    Ontario
    Jrejre; your right, the power don't have to be on to check the condition of the elements. A simple "continuity" tester is all that's needed. They are normally incorporated within any regular voltage tester.

    Btw, has the Dip tube ever been been eliminated as being the cause of the problem? Just a thought.
  12. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,831
    Location:
    Cave Creek, Arizona
    water heater

    I am not trying to make it difficult. In fact with a combination snap around ammeter and voltmeter, ALL the tests can be completed in about the time it takes to remove the wires from the elements to perform a continuity test. And it is more accurate because you can tell if the elements are acutally using current and if so using it correctly. But I would not start changing elements, (except for the fact that his are too small assuming the house wiring is adequate for 4500 watt elements), or anything else until I knew the real problem.
  13. lybush

    lybush New Member

    Messages:
    5
    Thanks for the link to the heater element wrench.

    Also, from 'HJ' response: It sounds like the heater elements can be changed WITHOUT draining the tank. Is that correct???

    In addition, one response says that I may use elements of greater wattage taht came with the system. I have #10 wire. 220 v, from the panel to the heater. What size elements are recommended for that???

    Thanks all for the very useful information.

    [Wish I had a plumber in the family] and a Dentist!!
  14. jrejre

    jrejre New Member

    Messages:
    61
    Location:
    Minnesota
    lybush, do you own a combination snap around ammeter and voltmeter?
  15. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,143
    Location:
    New England
    In other words, an inductive loop ammeter?
  16. lybush

    lybush New Member

    Messages:
    5
    No, Sir.

    I just own a regular V/a/ohm meter.

    Even with the power on I should be able to touch the ends of the elements and see if voltage is there. But that would only tell me if the Thermostat is on and calling for heat. I wouldn't learn much if neither is calling for heat.

    But, is it TRUE that the elements can be removed WITHOUT draining the tank?

    That is what I'd like to learn now.

    Len
  17. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,143
    Location:
    New England
    Don't know about removing them without draining, but you can tell if the element is nominally within spec by shutting off power, disconnecting the leads from the element contacts, then using your ohmmeter, check for continuity through the element. Just like a lightbulb, if it is open, it is shot. If you could look up the specs, you might be able to determine the cold resistance value range, but the gross test of is it broken, is easy. My guess is that cold, you might see an ohm or so, but it will look very much like a short. Now, it would be 220*220/2500 = ~97 ohms for a 2500 watt element using 220v once hot, but you can't directly check ohms while hot.
  18. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,831
    Location:
    Cave Creek, Arizona
    elements

    Turn off the water valve and electricity. Open a faucet, momentarily to relieve the pressure, and then close it again. Remove the wires from the element and have the new one ready for insertion. Have a piece of towel or paper towel handy and unscrew the element. When the element comes out, press the towel into the opening, around the element, to limit the amount of air that can enter the tank. Pull the element out and shove the new one in and tighten it. The whole process can usually be accomplished with only about a half cup of water leaking out.
  19. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,143
    Location:
    New England
    The old finger over the top of the straw trick :) . Neat, I'd not have thought of that. Guess that is one difference between a pro and a DIY'er.
  20. lybush

    lybush New Member

    Messages:
    5
    Thanks, all.

    I believe I have all the information I need to tackle the job.

    You have been extremely helpful and I appreciate your knowledge and expertise.

    Len
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