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Water heater thermostat evidence of failure (C) Daniel FriedmanElectric Water Heater Diagnosis & Repair FAQs
Older Diagnostic Questions & Answers on How to diagnose & fix an electric water heater

Older electric water heater diagnosis & repair questions & answers:

These Questions & answers about how to troubleshoot and fix an electric water heater, calorifier, geyser that is not working properly can help diagnose and fix the problem.

In this article series we explain how to test and repair an electric hot water heater that is not heating at all or is not producing enough hot water. We start with simple basic checks and then move to testing and replacing bad controls or bad water heater elements.

The articles at this website will answer most questions about electrical water heaters as well as many other building plumbing system inspection or defect topics.

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Older Q&A Help to Repair an Electric Water Heater / Calorifier / Geyser

Electric water heater thermostat and electrode access panels (C) Daniel Friedman

These questions & answers were posted originally at ELECTRIC WATER HEATER REPAIR GUIDE - home. Be sure to review the diagnostic suggestions in that article.

On 2015-02-02 by (mod) - why is our water heater temperature just warm, not hot?

Rick

If the water starts out plenty hot then runs tepid quickly the lower electric water heater element is probably burnt out;

If all of the hot water coming out of your water heater is tepid (not hot) then the upper heating element may be burnt out.

Or one or both electric water heater (geyser, calorifier, cylinder - various names for the same thing) thermostatic controls could be defective.

If you have about as much very hot water in volume on your water heater's data tag (like 30 gallons) that's about as much as you'll get at once from an electric water heater; electric water heaters are the slowest to recover.

On 2015-02-02 by rick

Temp.fluxuates from hot to just warm what could be the probem

On 2015-01-01 by (mod) -

Yes ir sounds dangerous to me, risking scalding burns and an unsafe water heater.

On 2015-01-01 by Tracy

My nan has boiling hot water Coming from her taps. She has warm air heating but is not working at the moment. The water is heated by an immersion heater is this dangerous.

On 2014-11-28 by (mod) -

Gayle those two observations may indeed occur together. You don't say how your hot water is made but it sounds as if it is dangerously hot (risking scalding burns) and that a water heater limit control is not working.

On 2014-11-28 by gayle

i have air in the hot water pipes and now the water feels hotter than the 120 degrees its set at.

On 2014-11-10 by (mod) -

D.

You found a potentially fatal hazard. But it's current flow (Amps) not voltage (Volts) that trips a circuit breaker. If little or no current were flowing the breaker would not trip unless perhaps it was a GFCI device.

On 2014-11-09 by D.

had voltage on water pipes and also on shower control knob,read it to be 70 volts.trace it to shorted lower element in water tank.why didnt reset button trip on water tank,or why didnt my breaker trip?

On 2014-10-20 by Gatorgirl

Since late spring, our thermostat has been turned down to 50 degrees. Our household consists of 7 people, so our hot water heater still works overtime between showers & dishes.

For the 3rd time in as many months, we have gone away for the weekend to come home to a tripped furnace. This only has happened when no one is using hot water (& heat by process of elimination) for more than 48 hours.

This same phenomenon happened last year a few times and a stumped plumber replaced our thermostat, breaker, motor, oil filter, and draft regulator in hopes that 'one of those may be the culprit.' Obviously, they weren't. Any ideas as to what may actually be causing this?

On 2014-08-21 by Anonymous

have a water heater about 3 yrs old,, every time we go away for a week or so we shut the tank off now all of a
of a sudden we have no hot water,,, everything has been checked out,,, reset and even the element has been changed and still no hot water. There is electric going to the heater and the reset has been utilized,,, any ideas what the problem could be,,, appreciate your help.

On 2014-08-03 by (mod) -

Richard,

Most likely an oil burner retrofit is what's needed, which may also include combustion chamber re-lining and other safety modifications.

On 2014-08-03 by Richardlinton@msn.com

I want to change my gravity feed furnace that is oil powered to the same system that will be electrically powered

On 2014-05-15 by (mod) -

Robbie, click to enlarge the page top photo and you'll see the red "reset" button on the electric water heater's thermostatic control.

Watch out: don't keep resetting the control. If it pops repeatedly something else is wrong, unsafe, and needs repair.

On 2014-05-15 by Robbie

I have a strange problem with my electric water heater only producing minimal warm water (not hot) before turning cold. I turn my upper thermostat way down to make sure the lower element gets power. I can see with my multimeter that the lower element reads about 240v across its terminals.

I leave it like this overnight, in the morning the bottom element is still getting 240v but there is still very little warm water if any, not enough for the kids to get a bath, they scream because its too cold.

I hired a plumber the other day because I couldn't figure it out. He said my water heater needed to be "reset", and my wife told me on the phone the water was coming out super hot 10 minutes later. This doesn't make sense to me because how could the elements be getting 240v if the hot water heater needs to be reset.

I called the plumber to ask him, but unfortunately his english is poor and I couldn't understand exactly what he was saying, but sounds like he said there is a "hard to find" reset switch somewhere. The red/brown ECO switch is certainly not hard to find and it doesn't appear to be tripped, so what could he be talking about?

On 2014-05-12 by (mod) -

Mark, that sounds like a bad sensor or bad thermostatic control - and it's unsafe. I'd try replacing the temperature controller.

On 2014-05-11 by MarK

Hi my hot water tank is malfunctioning was wondering if anyone ever heard of this...my thermostat is set at 150 degrees. So when my hot water tank heats up my water it get to a temperature that is extremely hot way above 150 degrees and then is sets off my reset. I thought to change my thermostat and did but it still is doing the same thing any ideas ?? Thanks

On 2014-03-18 by Anonymous

Thanks will do and get back to you

.? Why the air burst , they only started when heater went on the blink.

On 2014-03-18 by (mod) -

Bill, I'd check for a loose wire or a defective thermostat in the water heater.

On 2014-03-18 by Bill

Also when turning on the hot water I get a few second burst of air. This does not happen on the cold water side

On 2014-03-17 by Bill

Electric hot water heater will work for days then quit producing hot water then start again without resetting breakers, reset switches or anything at all, then quit again

On 2014-03-05 by (mod) -

Sounds right Ralph; basically the number of components to test is pretty limited: thermostats and heating elements and wiring, so you should be able to figure it out.

Sometimes just exposing the components by opening the access cover will show something obvious like a burned component. If I don't see that, usually the next thing I check (because it's so easy) is the individual heating elements (with power off and wires disconnected).

keep me posted, what you learn will help others.

On 2014-03-05 by Ralph

My heater is the non-simultaneous type so suppose I need to stay with the testing a little longer to see if it is switching from the bottom to top and go from there.

On 2014-03-04 by (mod) -

A.O. Smith (water heaters) has an excellent service handbook that explains these operating modes and instead of flip-flop they call it "non-simultaneous operation" of the electric water heater elements.

It is possible to convert some flipflop electric water heaters to operate the two elements simultaneously but as AOS points out you can't do that if the total amperage draw exceeds the circuit and equipment rating (say 40A).

Yeah I don't know either - it depends on the heater. Quite a few of them run one first and then the second as needed. Most are what we call "flip flop" electric water heater systems.

When the tank is full of all cold water, the upper thermostat flips on, heats up the water in the upper portion of the heater.

That's also where hot water exits to the building - from the top of the tank at the hot connection.

Once the temperature set on the upper heater's thermostat has been reached, the
thermostat control will then flip power down to the lower thermostat that controls the lower heating element.

The lower thermostat switch will turns on the lower heating element and that in turn heats water in the bottom of the
water heater until that water reaches the temperature setting on the lower thermostat.

Now the whole water heater is "hot". Of course life is more complicated. When the water heater is in use cold water is entering at the tank bottom (out of the end of the dip tube) but also somewhat mixing up water in the tank. If the upper tank is still hot, cold water entering in the tank bottom will contact the lower element and thermostat and those will turn back on.

On 2014-03-04 by Anonymous

Thanks for responding DanJoe, I checked the element and it tested good with a meter. didn't know if the botton thermostat had to be satisfied before the top element got power or not. Thought maybe both elements came on at the same time but don't know.

On 2014-03-04 by (mod) -

Ralph, not all heaters are wired the same so you'll want to check the manual for yours. but it's common for just one of the 2 elements to burn out. Or a top thermostat control controlling the top element could be bad.

On 2014-03-03 by Ralph

I have a kenmore double element water heater that is not working correctly. the bottom element comes on and seems to work fine, however the top element never get power to it for some reason. In my rational it appears to be a thermostat but which one. Is it the one at the bottom element or is it the one at the top element. Has anyone had this problem.

On 2014-02-13 by (mod) -

Arsie,

I'm not sure; is it possible that the incoming water supply to your portable heater is already heated ?

Keep in mind that many water heaters simply add heat to whatever temperature the water is when it enters the heater. If your portable unit was designed to start with cold water input and someone connected it to a hot water supply you could end up with a scalding burn hazard.

The other less likely explanation is that the unit control was damaged during moving.

If you tell me the brand and model I may be able to find more details.

Daniel

On 2014-02-13 by Arsie

Good morning sir just wanna ask if you have any idea of my problem
we had a portable water heater on our house(bathroom) at first it is working fine..

and then we move house and we dismantle it (take note: we just unplug the power source and water source)
and then we installed it on our new place (house) but then it seems to work fine but it is to hot even i turn the knob lower it is stil very hot..what is the problem or cause of it.. please help anything we can do to fix it.?? thanks and best regards and more power to you..

On 2014-02-04 by (mod) -

Debbie, that's certainly an interesting question; If the electric water heater was unplugged, perhaps nevertheless the water it contained was still hot.

I have seen scale and debris clog the outlet to a water heater, or a clogged or damaged dip-tube interfere with water flowing into the heater from the cold supply - thus not pushing hot water out to the house; from your description it sounds like a valve or pipe clog problem.

But what leaves me confounded is that you say you get a good flow but of cold water at the taps at other times.

Baffled in Poughkeepsie.

Let me know what the service tech says and does.

On 2014-02-04 by Debbie

Hi,

Our water heater has spontaneously stopped producing hot water three times in the last 2 - 3 months. Each time, my husband has "fiddled" around & wound up stumbling upon a way to get it started again, eventually. He's not convinced he knows what he's doing & the fixes seem to be temporary. So, we're looking for a true solution.

Each time it has happened there is just no hot water at all, even with taps turned to full blast hot. Last night, while the water heater was still unplugged for my husband's tinkering, a surge of hot water came through the pipes, sending out a strong wave of hot water to each faucet that was on. It has been operating fine again since then (but this was just last night).

Ideas about what we should try before we call a repair person or replace the water heater? It's a Rheem Powervent 2, 40 gallon tank, 7.5 years old.

Thank you!

On 2013-04-05 by Eric

Last round of questions. So, for whatever reason, I've been able to switch the breaker on and have hot water. But I've also notice that the breaker got warm and, when I put my nose right up to it, smells warm. Not hot, but warm. Any thoughts? Heater elements drawing too much? Breaker wearing out? Both? Something else?

It gets a bit more interesting re my Kenmore. I'd switched the circuit breaker back on earlier this evening for 45 minutes.

No hot water. I could have kicked myself. I should have out my ear to the water heater. This unit has a rotoswirl, which you can actually hear with your ear pressed against the tank.

Switched it back on. I can hear the rotoswirl. I'm now waiting to see if I get any hot water in another 30 or 45 minutes. If I do, then it seems to me the answer is clear. It's either the breaker or something internal to the unit (both heating elements?) that's operating intermittently.

If I don't get any hot water, then it seems to me the culprit is far more likely to be the breaker. Either way, I'm having the breaker checked out by an electrician and Sears return to check out the water heater from stem to stern. Again. Sound like a plan? Any suspicions based on your experiences?

On 2013-04-05 by Eric

Here's my situation. I have a Kenmore Power Miser 12. All was fine until we woke up two days ago without any water.

Stone cold. For about a week prior to that, we'd noticed the water being superhot in the morning and then cooling off to normal once used in the a.m. When we've had this happen before it's been because of a thermostat failure, an element failure, or both.

I tried resetting the thermostats but didn't hear a click. Turned the breaker on and off for that. Hot water came back. I assumed that I just didn't hear the click. Unit under service contract.

Tech came out today. Figured it was the thermostats and replaced these. Then ... no hot water this evening. Circuit breaker hasn't tripped. I've tried turning it off and on. Still no hot water. Is it possible that the breaker has simply failed? And if so, what are the possible reasons? Breaker is Square D, 30A, full size, double slot in the panel. Not sure how old it is, but may be fairly old.

On 2013-03-29 by (mod) -

Jeremy,

If you've replaced a control panel twice and have another failure I have to suspect that the problem is elsewhere as we have discussed.

On 2013-03-29 by Jeremy

Hot water control panel replaced twice...hot water for awhile then goes cold.

On 2013-03-20 by (mod) -

Jeremy,
Over at our articles on ALUMINUM WIRING one can read that though there is ample misinformation, even disinformation about the root cause of aluminum wiring connection overheats, damage, fires, the root cause is not thermal expansion but corrosion -microfretting - oxidation, increasing resistance, and thus overheating - in a runaway model.

On 2013-03-20 by (mod) -

Ron,

If the thermostatic control won't reset or won't stay set I suspect EITHER a failing heating element or a failing thermostatic control.

On 2013-03-20 by Ron

I have an electric water heater that just turns off everyonce in awhile. Sometime I can reset the red bottom near the top element and I can hear it turn back on and it heats the water well.

Other times it wont even reset by pushing the red button. I will come back an hour later and i can hear it heating again. I think its possessed. Your thoughts

On 2013-03-19 by Jeremy

Daniel,

All wiring between the breaker box and the water heater is copper; there is no visible evidence of overcurrent (burnt wires, etc).

Frankly all the connections still look new. The only aluminum wiring is the main wiring bundle entering the circuit panel from the outside, and it looks satisfactory as well. Once I verified that I installed a new (Pushmatic) breaker and it too tripped within 15-20 minutes.

I intend on upgrading the circuit panel, but at this point I still haven't ruled out an electrical fault in the water heater.

The topic of aluminum wiring is fascinating... do problems arise because of the different heat expansion rates of aluminum and copper? I can see where this would pose a problem at aluminum/copper splicing.

wiring photos to follow...

On 2013-02-12 04:53:35.485152 by David G

My water heater gets too hot with the temp set to the lowest, then the water heater trip's. The elements have been tested and they both pass the grounding test and the resistance test,

I noticed that it powers the top then changes to the bottom as it should. But the bottom never continues to heat the water until the heater trip's. Does the upper thermostat turn bottom off when the bottom is finished? Or does the bottom have it's own switch for when it's done heating the water? Thanks in advance!

On 2013-01-30 22:48:18.196399 by george moore

My thermostat has tripped a couple times now,my question is does both elements heat at the same time,saying is their voltage present on both at the same time?

On 2012-01-15 20:28:32.274233 by Norgo

Very clear and complete explanation. I went through them all. Problem was the heater high limit cutoff switch. And it simply needed to be reset. I'll keep an eye on it. Thanks

Question: white water after installing a new water heater

(Mar 12, 2016) Wanda Loadholt said:
With a newly installed electric water heater, is it normal for my water to have an white appearance?

Reply:

Run some water into a tall clear glass and watch it. If the white disappears you may be seeing very fine air bubbles - a condition that should stop on its own.

Question: 5 seconds of hot water

(Mar 19, 2016) Ruby White said:
My electric has hot water for maybe 5 seconds, then it gets cold. I changed the upper and lower elements, and still have the same problem.what should i do now?

Reply:

Ruby

5 seconds of hot water sounds very strange. If only an upper element were working you'd still have gallons of hot water before running out, while if only a lower element were working you'd at least have a larger volume of warm water.

Only if yours is a demand-type (tankless) water heater could I explain what's going on.

Question: dried foam looking stuff at top of A O Smith water heater

(Apr 6, 2016) R paglia said:
I have dried foam looking stuff on the pipe on top of my ao water heater. What does that mean?

Reply:

R Paglia

I can't say as I don't know what you're looking at: if it's crystalline -looking and fragile and located at a point where there could be a small water leak, that's probably what it is: mineral salts left behind from a leak.

Question: OK to disconnect lower heating element?

(Apr 18, 2016) Ozcar said:
can I disconnect wires on Lower heating element has an overnight repair to prevent breaker from tripping?

Reply:

Yes Ozcar,

with this warning:

Watch out: the short circuit that is causing the element to trip could be in wiring, a control, or at the heating element itself.

With power off to the heater, disconnect the wires and cap them off and WATCH OUT as someone touching live wires is likely to cause a bad shock or death. Eliminating the lower heating element will mean that you will have less total hot water quantity.

Question: suction noise and no hot water after installing new gesyer

(May 14, 2016) David said:

Installed new electric hot water heater and when we turned the water on there was a suction noise and no hot water will come out of faucets. What could be the problem?

Reply:

David I don't know, but from your brief question it sounds as if no one turned on water and re-filled the tank and then ran water until air was removed from the system. All of those steps should be done before turning on an electric water heater - otherwise the heater elements will burn up in a flash.

That creates a new sucking noise as money continues to leave your wallet.

Question: single-element water heater not working

(May 16, 2016) John jones said:
My hot water heater only has one heating element I have replaced the element and the temp control box and steal don't have hot water

Reply:

Check that there is actually electrical power to the components.

Test that the new heating element is good.

Check that the thermostat has not tripped.

Question: beeping water heater after replacing fuses

(June 4, 2016) Teresa brown said:
Just replaced fuses in hot water heater breaker box- when turned breaker box on a high pitch beep beep noise sounded and after that it worked.

My dad said the box didn't have the technology to make a noise to let you know it worked. Please simply answer does it or not. He is 88 and not technology savvy. This is important for me to be respected in intelligence. Thank you

Reply:

Teresa, I'm sorry but we can't know what technology is in your water heater or circuit circuit breaker with so little information. In general I agree with your dad, but then, we don't know what heater is installed, in what country, of what brand, model, age.

First take a look at the installation and operation manual for your water heater as surely that will tell you how the controls work and what signals might be provided.

If you don't have the manual for your water heater, check the heater's brand, model, and serial number and you can almost always find a free, downloadable instruction manual from the manufacturer's website. If you have trouble doing that, use the page bottom CONTACT link to send us a photo of your heater and its labeling and we'll see if we can help.

Watch out: If the breaker trips again I'd leave the heater off and ask for repair help from an experienced plumber or electrician as continually turning it back on could risk a fire or shock.

Question: water not hot enough in cold weather

(June 7, 2016) Jason said:
During hot weather (30 degrees Celsius) the water from my hot water cylinder is very hot - but in winter (-4 Celsius)I need to turn the tap nearly to full to get a warm shower

Reply:

Find and insulate un-insulated hot water piping; that may help.

Still if the incoming water temperature in winter is significantly lower than during hot weather, you may indeed have to set the heater's temperature up; that's because the incoming water is so cold that it cools down the reservoir of hot water in the heater more quickly.

Question: bottom water heater elements keep corroding rapdily

2016/06/18 David Kettleburgh said:

We bought a house two years ago. All electrics replaced about two years before that. Hot water is heated electrically. Was OK for first 18 months after we bought house but suddenly bottom elements in hot tank have been corroding and shorting electrics.

They only last five or six weeks - latest one fitted on 13 May and went today! They have been fitted by different plumbers, with good reputations. What is likely cause and cure please? Thanks!

Reply:

I don't know, David, but I would check for

- a bad sacrificial anode in the water heater

- errors in electrical wiring, shorts, stray currents

- wrong heater element wattage being installed

- defective heater thermostat that's not shutting off the heating elements

- corrosivity index of the water supply



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