Electric Water Heaters

By May 25, 2019 Electrical, Plumbing

Estimated reading time: 7 minutes, 51 seconds

Typical Electric Water Heater

Electric water heaters come in many sizes and shapes. (I recently found one in a basement of a 1938 home that looks like a washing machine). Most are cylindrical. They all provide years of service and have gotten much better insulated. This alone is a good reason to replace an old one. If you get over 10 years of service you have gotten your moneys worth. The sure sign of failure is a leak, usually trouble free, they can have some tricky to diagnose issues.

Gas water heaters recover quicker as a rule, be sure your heater is ample for the number of bathrooms you have in your home.

Ground water in our area is about 65 degrees. Warm water is about 110 degrees. heating it quickly takes a lot of energy. That is why storage makes sense and electric point of use units don’t work so well.

When they go bad we need to troubleshoot, often a small investment will keep the thing alive for a long time. Fortunately, there are no moving parts  which makes them fairly easy to repair. The problem is that most of them run on the dangerous 220 volt power, that can be life threatening. Occasionally a nagging problem with intermittent symptoms can take a long time to ferret out.

How do they work

Electric water heaters all work the same way. they have elements that are immersed in the cold water that turn on and off depending upon the temperature of the stored water. They usually have 2 elements that work together or separately depending upon how much recovery is needed. The bottom one is the workhorse and the top is the top off one. Cold water is dropped in on the bottom and the hot water is dispensed from the top. The temperature is adjustable with a screwdriver beneath the access panels. (use caution this is high voltage will can melt tools, and injure you severely or worse.)

When problems happen

There is a logical approach to these problems that starts with identifying what the symptoms are then doing a head to toe exam. Replacing a water heater technically requires a permit, but that is rarely done (even by professionals.)

Warm water likely problem

  1. The top elements is not working. This could be caused by a faulty element or thermostat
  2. A dip tube could be broken (if this is the real problem and all other issues are ruled out. (get a new water heater) chances are that it is full of minerals and on its last leg.
  3. Check the temperature that the water heater is set to low, you may just need to turn it up.
  4. In one home we found that the hot and cold water lines were reversed.
  5. Too much hot water used, A simple fix is to turn the temperature up (then folks will need to mix some cold in for comfort) this can cause a scalding issue for inhabitants. Be sure to inform everyone that things have changed.

No hot water likely problem

  1. Check the circuit breaker first
  2. There is an internal breaker too.
  3. The bottom element is out or the thermostat is faulty
  4. Check electrical connections at the elements and thermostat connections
  5. Check the temperature setting,
  6. Checking for burnt out elements. WITH POWER OFF. Remove one leg (wire) of the element and then check both screws for continuity. No continuity = faulty element. Drain tank to replace elements.
  7. The top thermostat is the controlling one, I always replace this one first if the elements are good.

Leaking problem

  1. Leaks are caused when the tank is corroded and at the end of its life.
  2. Other more common reasons for leaks are the fittings where the cold water comes in and the hot goes out. This happens more frequently than you think, corrosion or poor rubber gaskets.
  3. The T&P (Temperature & Pressure valve,) often on the side of a unit can which is designed to open if either of the limits reach dangerous will leak over time.

Too hot water

  1. Poorly seated thermostats, (they are held against the tank with pressure, a wimpy physical connection will prevent it from being satisfied and could run away overheating.)
  2. Thermostats set too high.
  3. Faulty thermostat.

Rare problems and assorted information

  1. Weird odors, This may be caused by water imperfections from the source, a well perhaps. Get help evaluating the issue from a local environmental laboratory by bring them a sample or consulting the water provider in the area. Sulfur smell is often an anode rod issue. there is a procedure for mitigating that problem in another post.
  2. Brown water. This usually happens when the water company is flushing their lines or a fire in the area which disrupted sediment. It is best to flush the lines of your home with cold water in the bathtub(where there is no restrictive aerator) until clean possibly 10 min. If left alone, any sediment will settle in the bottom of the water heater and can be drained out later.
  3. Weird sounds. This is usually a gas water heater problem but sediment from minerals being pulled out of the water settle on the bottom of the tank and if you are heating water through sediment it can tend to bubble and pop or burp.
  4. Dip tube problems. These are rare but do happen in older units. IMHO if you are working on your dip tube being the problem, it is time to replace the unit.
  5. Anode rod problems. IMHO if you are getting into problems with these things you have gotten your value out of the thing and take it in for the $10 at the recyclers. in rare cases you might have the wrong anode rod for your water conditions, Sulfur smell is rare but happens and is discussed in another post.
  6. Pressure tanks These are usually basketball size tanks that are used to take up the pressure of water expansion as the water heats up. They have a rubber diaphragm in them and usually go on the cold side. They can fail, I had one rot through and spray water all over the place. They can also rupture the diaphragm and be a useless ball. They are code now so we will see more of them as old water heaters are replaced.


Better water heater drain valve

Regular maintenance on every kind of water heater is a rare thing but very valuable. There  is a wimpy hose bib on the bottom that needs to be opened at least annually and release some scalding often brown or chunky water. The minerals that build up and settle on the bottom need flushing, the problem is that they clog the stupid plastic valve. Here is a replacement solution that should be considered.

I have found a great replacement for the valve seen here.


If you choose to work on your own, I caution you that this may be a big mistake. Countless hours can be spent fiddling with it. There is also the risk of serious bodily harm if for some reason you get scalded or electrocuted. The best diagram and troubleshooting guide I’ve ever found was at a local hardware store. I then had to use highlighters and write all sorts of notes on it to make sense to me.

Pearls of wisdom

  1. Drain it before you work the darn unit (Using a compressor can speed things up)
  2. Refill it before you turn the power back on (A dry fire will burn out an element in a heart beat)
  3. Use a professional when you feel like you are over your head. The service call is cheap compared to using sick time to recover from an injury.
  4. The 50 gallon size is the most economical, in fact we often pay $100 more for the smaller ones.
  5. I replaced a 95 gallon one and we could have gotten two 50’s for less.

I had one hilarious failure when attempting to drain one. The compressor had pressurized the heater and the majority of water had been drained but no rush of air out of the hose so I opened the valve a little more. That is when the entire valve unscrewed and I got a sediment and sludge shower, thank goodness the water wasn’t  hot.

Tank-less or point of use electric

These are not practical in the united states. I had a client that wanted to go off the grid and use photovoltaic cells to heat her tank-less water heater. The truth is that they take so much energy to heat ground water that you would likely need to increase the size of your electrical panel to service the thing. I have seen some used in commercial applications for hand washing sinks that look and work well, so as the technology improves there may be better ones on the market.

Your comments are welcome. To ask questions or get more information about fixing stuff, click here to email me directly, or call 208-639-1808

I do these things during non-Levco time to be sure it doesn’t interfere with the Remodeling business. Repairing things and understanding homes is just another passion of mine. or visit our contact page.

Disclaimer: Some of these images came from the WEB. If they are yours, and you object to them being used, please claim them and I will gladly remove and replace them at once.

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