Elec water heater

[Young Ed]

Unpleasant surprise this spring the cabin water heater stopped heating at all. Goggling says the upper thermostat controls both and is a common failure. So yesterday I ran up there with one and still don't really have hot water. If you hold your hand under the hot and then the cold you can feel a little difference but it's still far from even warm. Unfortunately I didn't think to grab a thermometer. Buddy that was with managed to get a really ancient volt meter going and we confirmed power at the top thermostat and element. Nothing to the bottom which according to one article we found is expected. So time for new elements? Hoping to get this right as it's 120miles to the cabin and once their the closest good sized hardware store is 50miles.

[TodFitch]

I am not an expert on that style of water heater but my parent’s last house had one. It is my understanding that there are two temperature sensors, one for each heating element. And they are wired such that if the upper heater is on then there is no power to the bottom one.

 

The concept is that the water at the top of the tank is heated first since hot water is drawn off the top of the tank. Then the whole tank is heated using the bottom heating element. When no water is being used the whole tank will be kept hot. When hot water is drawn off the top of the tank you have the whole tank of water, say 40 gallons. As the cold water rises the lower heater comes on for a while but it doesn't have the capacity to heat the whole tank very fast. Eventually the cold water gets up to the upper heater and temperature sensor which then turns on the upper heater. That heater has a smaller volume of water to heat so it can do a better job and it can give you another 10 or maybe 20 gallons of hot water before the cold water reaches the hot water outlet at the top of the tank. Now, during the recovery phase, once the top of the tank is hot the lower heater kicks in to warm the rest of the tank which can take a much longer time.

 

Anyway, if the top element is burned out you will have power to it but no power to the lower element. And you won't have hot water.

 

With the power disconnected and the wires removed from the heating elements you can use a volt-ohm meter to check for continuity on each heating element. No continuity (with low resistance) then the heating element is likely burned out.

 

The heating elements on my parent’s unit would go out fairly regularly. Maybe one every 3 or 4 years. They would just corrode through. And it was usually the top one. They were pretty easy to replace. The only hard thing on theirs was that they had pretty hard water and Dad would insist on trying to descale the water heater any time an element needed to be replaced.

 

For what it is worth, our cabin is just under 160 miles away and the nearest hardware store to it is about 25 miles away. When we arrived there in May and opened up the building the propane fueled hot water heater started leaking from the bottom of the tank. Expediency resulted in getting a new unit in what passes for the local area which was more expensive that if we had the time to shop around near where we live.

[Young Ed]

Sounds like I'm on the right track then with the element replacement. This water heater is from 5-2011 so we've probably been on borrowed time. It does get drained every fall and sit empty for almost 1/2 a year though 

[TodFitch]

If you want to get into the weeds then this video might be interesting.

 

[Dave72dt]

Change both elements.  We had electric heaters for years and always found it was the bottom element that went bad first.  Lime buildup was a problem.  Temp sensor was on the bottom element as well as a reset button.

[Los_Control]

Just something to think about, I will also guess elements & the bottom one gets the brunt of the abuse.

Sometimes the tanks can fill with crud & literally bury the lower element, depending how hard your water is.

You will want to use some wire to see how much crud you can get out of the bottom.

I have seen them before where you had to remove the crud just so the new element would go in.

 

They have a sacrificial anode rod that is suppose to help, probably all gone by now

 

Depending how old it is, it may be ready to start leaking from being rusted out ???? You need a crystal ball to know when.

Does draining it every year and sitting for 6 months prolong it's life span .... or shorten it? ..... I really have no idea.

I know our old cars do not like it.

So thinking out loud ..... I wonder what a new replacement tank cost, vrs repairing the old one then it start leaking next year?

 

The first house I bought had what I thought to be the original hot water heater, it was made by the Edison electric company.

I was proud to own it, as it worked just fine til it did not.

The only problem was it had like  a voltage regulator with points to control it. The points started sticking on it & would not turn off the elements.

Then it would overheat & blow off water through the safety pressure relief valve. It would flood the basement, one side was a workshop other side a bedroom.

So there was water damage & safety issue if the old safety valve failed to work ........ after 3 time trying to fix it, I replaced it.

[9 foot box]

   About 15 years ago I installed an electric tankless water heater. Your family could all have a hot shower, and never run out of hot water. I can turn the temperature down to 95 degrees and run it through my pressure washer. It’s on demand, so there is no waiting to heat a tank of cold water. There are special valves that should be installed, so you can flush out the water with air or pump a vinegar solution through it. I suppose it would depend on if you have a large enough electric service box. Two new elements should fix your problem but it’s something to think about for the future. I had to replace one element a few months ago. I disconnected the three elements to check them individually with an ohm meter for an open circuit on the faulty one. Rick D.

[Young Ed]

I'm hoping the yearly draining would have flushed out and kept the crud from building up but I will grab a coat hanger just in case. Setup is 12y old so I don't think it's due for full replacement yet. No signs of any rust but I guess I'll see what it looks like when I pull that lower element. It's located under the cabin in the crawl space so if it did start leaking it wouldn't wreck anything