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

Electric water heater diagnosis & repair questions & answers:

Questions & answers about how to troubleshoot and fix an electric water heater, calorifier, geyser that is not working properly or that's not heating water at all. We address problems with electcric water heating elements, controls, thermostats, wiring, temperature control, noises, and de-scaling.

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.

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Questions & Answers Explain How to Repair an Electric Water Heater / Calorifier / Geyser

Immersion type water heater thermostdat discussed at InspectApediia.comThese questions & answers were posted originally at ELECTRIC WATER HEATER REPAIR GUIDE - Be sure to review the diagnostic suggestions in that article.

Reader Question: what do I do if after replacing the water heater heating elements I still get no hot water?

I put in both heating elements and the upper thermostat and still cant get hot water what's should i do next - Earl Baker 2/19/2013

i have replaced both elements @ thermostats @ the reset switch but the reset switch
keeps tripping, this is on a electric water heater what else could it be? - Pat 2/20/2013

@Pat---I got same problem. Changed out everything and still trips red reset. Did you figure it out? - Bill 3/16/2013

(Sept 14, 2015) jmbonino@comcast.net said:
I just had a new electric hot water heater installed and turned the thermostat up to about halfway and my water is still not getting real hot?

(Oct 22, 2015) Claire said:
Hi, I have a large electric boiler, on Monday a plumber changed both elements for me.

Since then I have cold water trickling out of the hot water tap when I turn it on. No hot. The pipes are hot to the touch but no hot water coming out of the tap and the pressure is dire. Is there anything I can do myself to fix the problem or should I call the plumber back out? Thank you for any advice :)

(Apr 23, 2016) jeannin thermostat said:

I replaced my heating elements last year. Woke up yesterday to no hot water. I replaced the thermostat and still no hot water. Can anyone give me a suggestion for me to try. I only replaced top thermostat should I replace bottom as well?

Reply: if hot water is not hot enough here's what to check

Jeannin: Has anyone tested the upper and lower heating elements to determine if they are working or not?

Pat and Bill,

The good news, if there is any, is that with electric water heaters the total number of parts to check out and diagnose is small enough that there's no reason not to expect success.

If you have replaced what sounds like ALL of the parts involved: heating elements and thermostatic controllers, then I have to guess that when the heater still is not working the problem will most likely be traced to one of the following, listed in my guess at order of probability:

Watch out: : Danger of death by electrocution. If you are not trained for safe electrical work hire an expert who is.

1. bad power to the heater - test for voltage at the wires coming in to the heater first; if nothing there go to the panel. If you have power at the panel but not at the heater, there's an open wire in the circuit

2. improper wiring connection during the repairs

3. installed defective or wrong parts. Check the heating elements for continuity and resistance as we discuss in these articles. Check the controller or thermostat - it should be allowing current to flow on a temperature drop and call for heat. Sometimes the thermostat high limit needs to be reset or replaced.

JM

Electric water heaters - at least the larger units - typically have two heating elements - an upper and a lower element. Each has its own thermostat that can be set to a hotter temperature.

WATCH OUT for scalding hazards.

Reader Question: overheating on electric water heater - water heater too hot, water too hot

I changed the element on my fathers boiler it only has a single top element
The old one was set to max so that's how I set the replacement

However I notice the metal cap was very hot and a day later it popped the reset with the brown wire not burnt but glazed like its been very hot
I have put it down to about 75% and reset it is this ok or still too hot? - Warbeast 10/22/12

(Nov 22, 2015) Anonymous & Taoinie said:
I recently moved into a new house and the electric water heater is too hot too touch and water from the tap is scalding.

I can't find the thermostat and it is chewing through our electricity. I contacted the landlord, he said he sent someone to look at it and they said it was fine. But it definitely is not normal. Do you know how i can repair this.

Reply:

War, I'm not sure where the problem lies on your heater, but I'd start by being sure that the replacement element has the same wattage element as the original one. If you installed a mis-matched electric water heater element it may indeed be overheating.

Anonymous & Taoinie:

the heating element thermostat or thermostats (two of them if there are two heating elements) are usually behind a removable cover and above or close to the heating element mounting point.

Watch out: turn off power before looking into the water heater or its wiring as there is a risk of death from electrocution.

Taoinie,

Point out to your landlord that a scalding burn hazard is a serious hazard for occupants and a liability for the property owner. That condition should be fixed now.

The location of electric water heater thermostats is illustrated in ELECTRIC WATER HEATER REPAIR GUIDE.

Watch out, there is live electrical voltage behind those panels, you could be shocked or killed.

Reader Question: water heater output water is just too hot

2 days ago we began getting extremely hot water from our water heater. Our thermostat is still set very low so we are surprised and confused. There is also a slight metallic smell in the water and slight odd taste. Can you help us determine what's going on. - Becky NOrthrop 10/2/12

Reply:

Becky,

Most likely the thermostatic control on your water heater has failed and needs replacement.

See ELECTRIC WATER HEATER HIGH TEMP CUTOFF TEST for details.

Watch out: failure to replace a bad thermostat and overheating hot water is dangerous and risks scalding burns or worse, a BLEVE - explosion.

Reader Question: the reset button keeps popping out on our electric water heater control

When I reset the upper t-stat with red button fire jumps from wires on t-stat= water heater is a state select water heater.- Richard Cox 2/6/12

(Nov 27, 2015) dee said: Reset switch doesn't click when pressed

Reply:

Richard, it sounds as if there is a short in the wiring, the element, or the control.

Reader follow-up:

Also, there was evidence that a short had occurred in lower element region as there were burn marks on or near cover or where there was an electrical malfunction, both elements have been replaced, and still no hot water, both elements appeared to be normal when removed.

Dee:

If the reset button does not "click in" when pressed then either

- it was not tripped and your problem is elsewhere
or
- electrical power to the equipment is OFF
or
- the switch is defective

Reader Question: why does hot water come out of our cold water spigot?

27 April 2015 Nick said:

Can a defective hot water heater make the cold water faucet hot?

Reply:

Nick,

"a defective hot water heater" is a bit of a broad term for me to give a narrow yes or now answer to your question. IN general terms, a water heater won't suddenly make cold water supply turn hot.

There are circumstances in which hot water may come out of a cold supply faucet even though the pipes are properly connected (hot to hot supply, cold to cold supply). Those include

1. Routing of cold water piping close to hot water piping, or close to another heat source (boiler room ceiling for example) combined with a period of dis-use of the water system can cause water resting in the cold water piping to become warm.

This situation is easily diagnosed by observing that water comes out of the cold water tap warm or even hot but as more cold water is run the water becomes and remains cool or cold.

2. By convection, in some building piping systems hot water can rise out of the hot water tank into cold water piping and even upwards in building cold water piping to the fixtures. This is most often due to the loss of all or part of the dip tube in the water heater

The dip tube both delivers incoming cold water (in the water heater tank) to the bottom of the tank and it also prevents hot water (from the top of the tank) from rising by convection into the building piping.

Question: water heater stopped working after main circuit breaker tripped

(May 17, 2015) David said:
My electric water heater worked fine until the main breaker to the house went out. After replacing it, all electric appliances, etc. work fine, except the water heater. I have emptied and cleaned the tank, replaced both heating elements and both thermostats. All wires to and within it are hot, conveying electricity. Why won't the elements heat up? Thank you.

Reply:

If you have replaced all of the parts to the heater and it won't heat water and if you have confirmed that power is provided to the heater, then I suspect mis-wiring or a defective part among those replaced.

Start by checking that the thermostat overheat relay is not tripped.

Question: does an electrical fire affect accuracy of water or hot water use meter?

(June 9, 2015) pickle said:
my hot water heater when last time guy clean filter reset red button work

(July 12, 2015) Anonymous said:
An electrical fire tripped the circuit breaker in my apartment does that affect the transmitter/meter in the unit to give and inaccurater reading of the meter

Reply:

Possibly, yes, Anon, if a water meter transmitter was exposed to fire it may have been damaged. But most likely I'd think it would either work or not - a binary choice.

Question: leak at hot water piping

(Sept 19, 2015) tony said:
I have a 2012 Lexington mobile home double wide with a bradford water heater with a pin hole in the hot water outlet pipe. I still have hot water , but when i taped up the leak, the leak seemed to be at the pipe joint seal. What should I try next?

Reply:

It sounds as if the leak repair was not successful; water leaking under the tape is appearing (perhaps) at the next pipe joint. Wipe everything dry and watch closely; typically taping a leaky water pipe is not a reliable repair nor a durable one.

Question: burned wires at the control on an electric water heater or geyser or calorifier or hot water cylinder

(Oct 7, 2015) cliff said:
I found a wire burnt . From element to thermostat . Hot water heater not working . Does any one know what may b wrong . Thank you

(Feb 7, 2016) bmosier54 said:
I have a whirlpool electric smart hot water heater. When the elements were bad they were replaced. There was a unknown leak, when power was restored still had no hot water. Looked at top element black plastic was melted some, and 3 flashes said sensor failure. Can the element be the problem for that or sensor is really bad?

Reply:

Check for

Question: leaks at water heater heating element

(Dec 16, 2015) James Johnston said:
I changed my heating elements on my water heater now it leaks around the element what can I do

Reply:

James

If a modest attempt at further-tightening the heating element does not stop the leak completely then

You'll need to

turn off the heater and let it cool
drain it
remove the leaky element
inspect the threads on the tank and element for damage; if they are not damaged, re-install the element using a non-hardening pipe sealant.

Question: can't find water heater power switch

(Feb 17, 2016) MrB said:
I don't have a breaker in my box for my water water. I tripped all the breakers (there's about twenty 20A and four 15A breakers) , I'm still getting power to my electric water heater. House was built in 2005. What else can I try? I probably need to change my heating elements (no hot water).

Reply:

Turn off your main circuit breaker or fuse.

If you turn off the main switch in your panel and the heater still has power then it has been powered through a separate box or panel or sub-panel, usually taking power off of the main switch.

Follow the wires back from the heater; it should be switched by a local panel close to the water heater or calorifier.

In an emergency you can turn off the main electrical power to the house then check using a neon tester, DMM or VOM to be sure power is off to the heater but the system is still unsafe if you cannot find the local shutoff for the appliance.

Reader follow-up:

(Feb 17, 2016) MrB said:

I've been in this house for 3 years now and there's the main panel (no main switch), then there's a small box outside that has a breaker for the septic pump and a 240 to control the pool equipment.

Even with everything off (tripped) on both boxes, I'm still getting power to the water heater. When I took the frame off of the main panel I saw where the power was coming into the house, and everything lined into the 20A and few 15A breakers.

I was hoping to see an indication of where the water heater was getting power, but I didn't. I even tried tripping the breakers for the two AC units wondering if it's jumped off of those. Nothing. I'm thoroughly confused.

Ok, my main ended up being located outside. I changed out the upper and lower thermostats the first day (still didn't have hot water) and the heating elements today (they tested good though) and I still have no hot water

. I have a 65 gallon electric water heater. I filled it up with faucets running to purge the air out of the tank, 6 hours later still no hot water. What else should I check ?

Limit switches were replaced too with the thermostats.

(Feb 20, 2016) MrB said:
Another question, my reset button is flush with the body of the limit switch (on both the old and new), is this correct. I try pushing it in, but it remains flush. I guess if pops out so it isn't flush when it trips. Is this so?

Moderator reply:

If the reset button is flush it's probably in its "on" state, that is, the system has not turned off on safety - when that happens the button pops up.

Your electrician will check for

- working circuit breaker to the appliance

- power to the heating elements

- proper resistance across the elements to indicate they're working, not shorted

- the function of the heating thermostatic controls

- that the reset button (that's flush or "on") and control is indeed passing current to the elements

Reader follow-up: bad circuit breaker

(Feb 20, 2016) MrB said:
Had a friend come and take a look at it, come to find out I have a bad 30A breaker (wires melted). I'll get that replaced in the morning.

Moderator reply:

B

I would much like to know the brand of the circuit breaker, to see photos of it (use our page bottom CONTACT link), and also to know if your heater is wired with copper or aluminum.

Watch out: IMO it is really dangerous for someone to wire up any electrical circuit or appliance without providing an easily-found and properly labelled main switch.

When a main panel has no main switch the "rule of 6" suggests that we need a nearby separate main switch for it. Your wiring system may bring power into the house at a point where there are several "mains" that can be switched off, one for the panel you describe.

Take a look at where power comes to the building outside.

Find the electric meter.

Notice where a cable from the meter enters the building.

Look inside at that same area for main switches.

If you remain stuck I'm sorry to say it's time to call an electrician.

(Feb 17, 2016) MrB said:
I'm going to upload some pictures to a 3rd party service. Maybe this is a sub-panel coming in from the main power company panel?? I don't know. I'll probably have to call them to get permission to cut the seal and see if I can cut power, I'm guessing that's how that works.

Moderator reply to photos by email:

Looks like a large GE panel with no main. There must be a main nearby. Perhaps if you follow that wire back towards where you see the electric meter outside you'll find the missing main switches for other features like the water heater.

Feb 17, 2016) MrB said:
I'm guessing the main is in the panel underneath the digital readout from the power company, could that be the case? If so, their seal is preventing me from opening that bottom panel on the outside.

Moderator reply:

There must be a main or a small group of mains to enable a homeowner or occupant to cut all power


...

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Or see these ELECTRIC WATER HEATER REPAIR FAQs-Older

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Electric Water Heater Repair Articles

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