Electric hot water heater making noise when heating.

Discussion in 'Water Heater Forum, Tanks' started by Charrie, Feb 2, 2020.

  1. Charrie

    Charrie New Member

    Joined:
    Oct 6, 2018
    Location:
    N. GA
    WP_20200202_005[1].jpg Hi All!
    The water heater is a 30 gallon US Craftmaster duel element electric standard tank. The heating elements are 4500W each and the wiring is only 12-2 but is only 6 feet from the electrical panel so maybe that is ok. I checked and the wire is not warm while the tank is heating.

    Back to the noise. We have lived here a year and the tank was new when we moved in. In the past couple of months I have been noticing a slight hissing sound when the tank comes on. Over the past few months it has become a little louder and higher pitched.
    Well yesterday my son and I drained the water heater and attempted to flush it but not much came out. Some sand like material, less then a 1/4 cup. We pulled the lower element out and looked in the hole at the bottom of the tank. There is still some sediment and a few larger particles on the bottom but nothing caked up though I think it can be flushed better. To flush it better we are going to have to change the drain valve. The one on it is plastic and you turn a screw in the center of what looks like a handle. The outlet hole is very small and I believe some of the particles may have clogged it up.

    Anyway, we put in a new lower element and I plan to clean the old one. It has a fair amount of white calcium build up on it though I have seen worse... So after flushing the tank and installing a new lower element, we are still getting the hissing sound. My son was taking a shower and I heard the tank kick on and start hissing. I grabbed the electric meter and checked the upper element and it was off so I know it is when the bottom element is on.

    We are on well water so I wasn't surprised to see some of the sand... Our system has a softener but we haven't been using it for the past 6 months. When we use the water softener we get a bad sulfur smell.

    Anyway any advice is appreciated.

    BTW this tank has the connections on the side of the tank with cold at the bottom and hot at the top.

    On the end with the threads is discolored because i used a brass brush to clean it.
    I checked the ohms and it was fine at 12.5 which i read is with in spec.
    Thanks
    Charrie

    WP_20200202_001[1].jpg
     
    Last edited: Feb 2, 2020
  2. Smooky

    Smooky In the Trades

    Joined:
    Apr 4, 2011
    Location:
    North Carolina
    It may be leaking at the TPR valve when it starts heating up. Make sure there is no water leaking out the TPR valve when you hear that sound.
     
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  4. hj

    hj Moderator & Master Plumber Staff Member

    Joined:
    Aug 31, 2004
    Occupation:
    Plumber
    Location:
    Cave Creek, Arizona
    If you used that type of element, it is a "high watt density" one so it gets hotter than a low watt density one, which can cause "local overheating" which could cause the hissing due to steam creation.
     
  5. Charrie

    Charrie New Member

    Joined:
    Oct 6, 2018
    Location:
    N. GA
    Thanks for the replies!
    I have checked the TPR valve several times and it is not letting any water pass through it.

    I used the same element for the replacement so it would be a high watt density. I have seen both types but never knew what the difference was till now, after I looked it up! Can I put a low density element in the tank without a problem?
    We were told that the water heater was new when we bought the house but I can't find any dates on the water heater. If the tank is only a year or so old, then that should be the high watt density element should be the original element. My son took a shower after we replaced the element and flushed the tank. He said that some blackish water came through the hot water line while he was waiting for the hot water to get to temperature. I also noticed black on my finger after trying to feel inside the tank around the element threads.

    BTW it seems to be getting much louder then it was just after we replaced the element unless is is just because I am paying more attention.

    Thanks in advance!
    Charrie
     
  6. Charrie

    Charrie New Member

    Joined:
    Oct 6, 2018
    Location:
    N. GA
    One other question.. would it make much difference if I replaced the 4500 watt high density with a 3500 watt low density other then longer time to heat the water. The reason I was thinking about this is because of the 12 gauge wire feeding the tank. How would it affect the cost to heat the water?

    Thanks
    Charrie
     
  7. phog

    phog Active Member

    Joined:
    Jul 29, 2017
    Location:
    Rochester NY
    No effect on the cost.

    Regarding the smaller gauge wire: you could measure the voltage drop caused by the wire with a multimeter. With the water heater on (thermostat actively powering an element, not just the breaker on) measure the voltage. Then take the same voltage measurement with the water heater idle (breaker on, neither element powered). Subtract #1 from #2, this is the voltage drop caused by the too-small wire when current is flowing.

    Multiply that number by the current, roughly 18.75A, and this gives you watts of heat being dissipated by the wire. (The current will actually vary slightly with the voltage but you can use this number to get close enough). This will give you an idea of how bad your present situation is.

    Say you measure 0.1V difference between element on vs idle, this means you likely have nothing to worry about, < 2W heat dissipation across the circuit is nothing even if it's all concentrated at a single point. If on the other hand you measure 10V difference, this is cause for concern.

    Please note that I'm not arguing against bringing the circuit up to code, just helping you understand what is going on.

    Finally, to answer your other question, the 3500W element would drop the current from 18.75A (which violates code for continuous current on 12/2 Romex) to 14.5A (which is within code). However I believe that code also specifies to follow manufacturer instructions on wire sizing if they are more stringent than NEC -- and those manufacturer instructions almost always specify 10/2 Romex even for electric water heaters that have 3500W elements.
     
  8. fitter30

    fitter30 Member

    Joined:
    Feb 2, 2020
    Occupation:
    Retired service tech
    Location:
    Peace valley missouri
    If water pressure out of the faucets drops clean or replace the aerators. Disturbing the lime in the tank will end up there.
     
  9. Charrie

    Charrie New Member

    Joined:
    Oct 6, 2018
    Location:
    N. GA
    Thanks for the advice. I haven't had time to check the voltage drop yet as I have to move the dryer out of the way to get to the tank but will here soon.
    The breaker is a double 2 pole breaker with a 20/30 amp with the water heater on the 20 amp and the 30 amp marked as furnace. Yes the furnace is electric and has 2 double pole breakers that feed it. One is a 50 amp and the other is a 30 amp. I will look at swapping out the wiring but for now will probably change the elements to 3500 watt.

    We are on well water and have to clean the aerators often as well as clean sand out of the toilet tank. I have a delta single handle shower faucet in my bathroom and have noticed it drips sometimes and I have to go turn it on and back off for it to stop. The PO spent $4k on a water system and yes there is no filters! The company he hired installed a water softener and peroxide injection system. That is another topic later though.

    I understand now about the high density element now thanks to HJ bringing it up. This very well could be a steam issue. WE have been here a year and I just don't remember hearing it till the past few months. I assumed the tank might be full of sand and other build up but it wasn't as bad as I thought it would be. I think when i change the elements out that I want to flush it again but need to change the drain valve. below is the oneon the tank now.
    drainvalve1.jpg

    images.jpg drainvalve1.jpg
    When draining the tank last time, i had to keep tapping on the valve to keep the flow going because it would become clogged up. The tank is located in the laundry room so I have to be careful to keep allot of water off the floor. I saw a pic where someone broke one of these plas5tic valves off while trying to remove it... I certainly hope that doesn't happen to me! Any ideas on the best way to remove one? I would like to replace it with a ball valve so the opening would be larger..

    Thanks
    Charrie
     
  10. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Counterclockwise.:rolleyes:

    I would consider
    Rheem AP12231C-1 Overall Length (in.): 6-1/8
    Rheem SP12231B Overall Length (in.): 3-3/4
    Rheem AP12231B-1 Overall Length (in.): 3-3/4
     
  11. Charrie

    Charrie New Member

    Joined:
    Oct 6, 2018
    Location:
    N. GA
    Thanks Reach. I think I would have to go with the AP12231C-1 because I am not sure that the other 3-3/4 would be long enough to thread into the tank.

    I have an idea I would like to run past you all. My laundry room is pretty full right now and to access the water heater, I have to disconnect and move the dryer and then remove a wall panel. In the drawing of the room below, I would add a short nipple, an elbow, anther length of pipe to pass through the wall, a full flow ball valve, and an adapter for a hose. Wold that work or would the 3/4 galvanized elbow cause a restriction that would get clogged up? If this would work then I would have easy access to flush the tank yearly. And yes i would remove the valve handle so that it doesn't accidentally get bumped and turned on!

    drainvalve2.png
    One last question though a different subject... I am going to build a new well house one day and would like to move the softener and peroxide injection system to the well house which is 300 feet from the house. Is the well house a good place for the equipment?

    Thanks
    Charrie
     
  12. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Interesting idea. I don't know if the thing about avoiding dead ends in potable water would be a problem here. If I did that, the elbow would be brass.

    That should work. After install, you will want to sanitize your plumbing, including to the house and in the house. Not that this stuff is not able to take really high pressures, so I hope the well house is not at a much lower attitude. If your new well used a pitless adapter, the well house would not have to actually be at the well. It could be closer to the house.
     
  13. Charrie

    Charrie New Member

    Joined:
    Oct 6, 2018
    Location:
    N. GA
    Thanks Reach. I remember you helping out with information on how to sanitize the well when we first moved here. I still haven't gotten to it yet!
    I have had several other problems since then like having to replace a 4'x21' culvert pipe under the driveway and wet leach field. Don't trust the seller when buying a home!

    Anyway I never thought about dead ends. So I was reading about stagnate water in pipes, bacteria, and corrosion. My mothers house is on county water and has some outside faucets that have probably not been used in 20 years! Here though, I am on well water that has coliform issues.
    Perhaps if I could make one of the 3-3/4 valves work, I could make a access panel on the wall that my diagram shows the pipe with the valve coming out. I should be able to reach in through the access panel and connect a hose. The problem there is that I think I would have to cut the sheet metal around the drain hole to allow the short valve to screw in all the way. The 6-1/8 valve would be too long and almost hit the existing removable panel.
    There is a Rheem AP11298 3/4 brass extension though that might work on the short valve.

    I tired a crude method of using my 4' level (at level) and sighting from my kitchen window to the well house 300' away and it is about the same level as the top of my kitchen sink. I think permitting might have been a bit lax when this site was roughed in. The 300' line from the house to the well is 3/4 pvc. The pump was fed with #10 wire with no neutral. There is a creek about half way between the house and the well so there is a drop of about 15 to 20 feet at the mid way point. I am not sure how that will affect the pressure. If I was smart, I would have thrown in a 1"pvc water pipe and 1"electrical conduit across the driveway while they were replacing the culvert pipe, but I didn't!

    BTW. In addition to the hissing sound from the hot water heater, I am now getting a chirping sound after the element has been on for a little while. i have not changed the element to a low watt density element yet until I get the parts for the drain. Chirping? Water boiling near buildup or sediment in the tank?
     
  14. Charrie

    Charrie New Member

    Joined:
    Oct 6, 2018
    Location:
    N. GA
    Thank you Phog, I finally got the time to measure the voltage drop and it was 7 volts. The no load voltage was 247.6V and with the water heater element on, the voltage dropped to 241.6.

    Should the calculations be made at 240V or 247V? I would guess that the actual voltage can vary at different times.

    7V total voltage drop
    131.25 total watts dissipated by 20 feet of 12-2 romex wire at 240V with a 4500 watt load.

    Not sure what to d0 just yet... I depend on my son to help with many projects and would need him to change the wire to 10-2. I still have to change the elements to a low watt density,change the drain valve, flush the tank again, and see if the noise goes away. Since my toilet tanks had a black slime in them, perhaps the tank does too!

    Thanks
    Charrie
     
  15. phog

    phog Active Member

    Joined:
    Jul 29, 2017
    Location:
    Rochester NY
    You would use the 247V number (and the measured resistance 12.5 ohms from your original post) to calculate the actual current = 19.76A. Then multiply the current by the 7V drop you measured to calculate the precise power dissipation = 138W. But very little difference from the 131W number you calculate, you're basically spot on.

    That isn't a crazy amount of heat assuming it's evenly distributed along the wire length. 7W/foot is definitely enough to warm up the conductor but probably not cook things. Basically your water heater wire is the equivalent of low power heat tape such as one you might wrap around a pipe in a crawl space to prevent freezing, or one of the heat cables people install in their rain gutter& downspout to prevent ice damming. Probably not hurting anything, as long as the heat can dissipate freely into the environment. You definitely don't want to have it encapsulated in closed cell foam insulation though, or bundled in the center of a bunch of other wires.

    Bottom line, you're definitely exceeding the continuous current rating for a 20A branch circuit (16A) and even are within a hair's breadth from tripping the 20A breaker. But not something to lose sleep over in the short term, just something to update when you can.
     
  16. Charrie

    Charrie New Member

    Joined:
    Oct 6, 2018
    Location:
    N. GA
    Thanks again Phog. This lesson has also helped out with my planning a new well house as I did some extra research into voltage drop, intermittent, continuous loads, an a few other things I will need to know. I think I will start another post on that since this one is about water heaters and put a link here so you can get to it easy if you like. I could probably use some help with the calculations and you seem to know your electrical!
    One question though about the well... there is no neutral at the well house an I would like to move my water softer and injection system to the well. All the electrical equipment is 110V so I would need a neutral. Will a step down transformer create its own neutral? If so, then how much power does say a 1 or 2 kva step down transformer use? I would only need about 2 amps to run the softener/injection equipment but would like to be able to turn the well pump off and have 110V available to run a power tool like a drill or skill saw on that part of the land since it is 300f from the house.

    Okay back to the water heater.
    While my son was taking a shower today, I listened as the WH element energized. I checked temperature of the wire and circuit breaker by touch. (Just remembered my son has one of those infrared thermometers!) Anyway the wire was just slightly warm to touch as was the circuit breaker by the time the thermostat was satisfied. I guess that if the tank was completely cold, it would run at least twice as long and the wire and breaker would have been much warmer.
    I can do most of the work mentioned in my last post except run the new circuit by myself. So I am really thinking about changing the elements out to 3500 low watt density elements for right now and see if that stops the noise. Later in the spring or summer I can change the wire and breaker out. It will have to be changed out at one point because I have a brand new 40 gallon electric WH in my shed I brought with me when I moved here. It was bought for my old house but never needed.. Too much money to just leave behind.

    The current breaker is a double 2 pole 20/30 and I would have to find a 30/30. there are some spare knock outs in the panel cover but I have never taken the cover off to see what it looks like in there. I don't know why they would have used the 20/30 if there was extra space in the panel.
    bq230230.jpg
    Thanks
    Charrie
     
  17. phog

    phog Active Member

    Joined:
    Jul 29, 2017
    Location:
    Rochester NY
    Sort of.. technically your home neutral is wire at middle point between two 240V "hot" conductors, ie 120V from each. "Neutral"
    specifically means the center point between two (or more) hot conductors.

    If you use a step down transformer you will have 120V output on a pair of wires, usable exactly the same as the 120V neutral / hot in your 3-wire 240/120V panel box. But, since the transformer output is only 2 wires you no longer call it "neutral".

    Of course this is just semantics. The answer to your question of "can i use the 120V to run other appliances/tools/whatever" the answer is yes.

    To figure out how much power the transformer uses, look at the efficiency. The higher the efficiency the less power the transformer draws at a given load. For example a 97% efficient transformer would "use" 3% of the electric current for voltage transformation.

    (The kva rating is essentially another name for kilowatts, 1 watt = 1v*a. So 1kW = 1kva)

    Last, i want to mention that you should pay close attention to ground bonding and safety if you plan on running tools off the transformer. Any time you're using electric and are in contact with the Earth (typically in a bathroom or kitchen, or anywhere outdoors) you need to be working off a GFCI protected circuit. Your transformer 120V output needs to be correctly bonded to earth ground & GFCI receptacle installed in order to safely use it for your tools... Otherwise you literally risking death! (It's not complicated at all to do correctly, but it is absolutely imperative to get it right)
     
  18. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Joined:
    Sep 2, 2004
    Occupation:
    Retired Systems engineer for defense industry.
    Location:
    New England
    Unless you can reference one side of the 120vac coming out of the transformer, things could get dangerous if using something with a polarized plug, since what would be assumed to be 'ground', would have 120vac on it as things are floating.
     
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