Electric Hot Water Tank still not heating after full rebuild

[MrMega]

I have an A.O. Smith Signature 100 40-Gallons Short 4500-Watt Double Element Electric Water Heater. Installed and ran fine for one year and 2 days, then nothing.
Tried eco switch and button did nothing. Assumed it was top element, bought a full rebuild kit; had a GOOD element removal took in it.
Still wouldn't work after element replacement and don't have time to keep playing switch-a-roo so I replaced everything; both thermo's and remaining element.
Been over an hour and a half and still no hot water. Power testing shows power is there.
I've replaced gas HWH dozens of times, including just the thermocouples when the tank was still good; I am stumped on what else can be wrong on this thing! I even re-checked power leads going in the top of the until.
No chance of mixing up wires (installed wires back a lot cleaner than they were originally, with thermostat straighter).

Element I took out were corroded some, but not "bad" and not burnt, by any means.

Not sure what else to do?!
Ideas??

 

[Twowaxhack]

First off you need the correct voltage at the top thermostat.

You should be able to hear the element heating if you put your ear to the tank.

You should get an amp meter and clip around one wire going to the element. If it’s heating it’ll show amperage. No amps being used, no work is being done. No hot water.

The top element heats first, when the top thermostat is satisfied the power switches to the bottom thermostat, if it’s calling for heat then the bottom element turns on.

If the top thermostat doesn’t get satisfied the power will never switch to the lower thermostat.

So…..

Check voltage at the top two terminals of the upper thermostat.

Check the wiring schematic

Check amps. Wattage of the element divided by the voltage gives you amps. Do the math.

Put your ear to the tank(if you can hear well) to see if you hear the element heating.

 

[Twowaxhack]

Did you dry fire the top element ?

Turn the power off to the water heater and remove both element wires.

Check for continuity between the two screws on each element. It should show continuity.

Then check from each screw to the bare metal steel tank of the water heater. You should not have continuity there.

 

[dmmsr]

Sounds like you have a good idea of what you are doing. But i figure i would ask anyway to make sure you did not make a mistake. Did you turn on the power before tank was full or purged of all air?

 

[Twowaxhack]

Sounds like you have a good idea of what you are doing. But i figure i would ask anyway to make sure you did not make a mistake. Did you turn on the power before tank was full or purged of all air?

Doesn’t sound like he has a clue to me. Parts changer. No offense intended.

 

[Twowaxhack]

Check and make sure you don’t have a hot water leak.

You could be heating the water but losing it immediately from a leak.

So check for a leak on the hot side piping.

 

[RonAKA]

I have zero experience with an electric water heater, only gas. However, there must be a temperature controller that detects temperature in the tank, and based on temperature closes a relay that provides voltage to the top element, the bottom element, or both. The check I would do is measure voltage (if you can do it safely to each element. And with the power disconnected to each element measure the resistance of each element. That should let you know if the element is at fault or if the controller is at fault.

 

[Twowaxhack]

I have zero experience with an electric water heater, only gas. However, there must be a temperature controller that detects temperature in the tank, and based on temperature closes a relay that provides voltage to the top element, the bottom element, or both. The check I would do is measure voltage (if you can do it safely to each element. And with the power disconnected to each element measure the resistance of each element. That should let you know if the element is at fault or if the controller is at fault.

The temperature controller is the thermostats. The thermostats press against the tank and the heat transfers into the thermostat to close or open the contacts.

Each element, upper and lower have 110v supplied at all times. When the thermostats close, it completes the 220v circuit and if the element is good it produces heat.

The best way IMO to check an element is continuity and to make sure it’s not grounded.

Then to prove it works, check amp draw.

4500 wattt element divided by the voltage equals the amps it should read. If the amps are too low or too high, replace the elements.

I outlined how to check the elements and sequence of operation in my posts above in this thread.

 

[MrMega]

Wasn't dry fired.. old elements still look good, and test out good; top was 12.13 or 12.23 Ohms... can't remember the bottom element, but somewhere in 13.xx
Ordered an amp meter and will be here tomorrow. Made new alligator test leads for multimeter today so I can check continuity through wires within tank tomorrow if amps check ok. Figure the power going down to tank "should" be ok since house was built in 80's and been supplying power all those years and wiring, which shows, is not cheap/thin.
@RonAKA - same here, I've worked on/repaired, installed or replaced a bunch of gas HWT's but where I moved now, there is NO gas to be used.. would have to get propane tank rented/set up and go that route, and from what I have heard, they're not reliable for refills out here in the country.
Can't be lost to a leak due to well water; would see/hear pump engage - the gauge it maybe 2' from the tank (and no sediment came out when drained it, although got just a slight tinting - like VERY weak tea - when refilled and was getting air out of tank before restoring power).
Hoping amp meter shows at normal mail delivery time tomorrow.. but more and more, it seems when I order anything important to do with in home or firearms repair, it shows up after 5pm (lol, or it gets lost).

Thanks for help / answers. I haven't fingered up amps, watts, etc. since college!! In fact, I had to get a new multimeter since my old one died (Realistic from Radio Shack - was top of the line way back then! Lasted 30 years!) When I find out watts wrong, will report back.

 

[RonAKA]

My issue is that I have never found a project that I could justify buying a clip on amp meter, and don't have one. So, I just measure resistance and voltage to calculate the amps.

The quick and dirty way to check the elements is to measure the voltage from one side of the element to the other side. If there is no voltage drop from one side to the other, then there is no current.

 

[Twowaxhack]

My issue is that I have never found a project that I could justify buying a clip on amp meter, and don't have one. So, I just measure resistance and voltage to calculate the amps.

The quick and dirty way to check the elements is to measure the voltage from one side of the element to the other side. If there is no voltage drop from one side to the other, then there is no current.

No, you’re calculating what the amps should be. Not what they are.

An amp meter shows work happening…..

When the element is pulling amperage it’s working. When it’s pulling the correct amperage, it’s working correctly.

A working test is the best test according to me and several manufacturers of the heaters

 

[Twowaxhack]

Wasn't dry fired.. old elements still look good, and test out good; top was 12.13 or 12.23 Ohms... can't remember the bottom element, but somewhere in 13.xx
Ordered an amp meter and will be here tomorrow. Made new alligator test leads for multimeter today so I can check continuity through wires within tank tomorrow if amps check ok. Figure the power going down to tank "should" be ok since house was built in 80's and been supplying power all those years and wiring, which shows, is not cheap/thin.
@RonAKA - same here, I've worked on/repaired, installed or replaced a bunch of gas HWT's but where I moved now, there is NO gas to be used.. would have to get propane tank rented/set up and go that route, and from what I have heard, they're not reliable for refills out here in the country.
Can't be lost to a leak due to well water; would see/hear pump engage - the gauge it maybe 2' from the tank (and no sediment came out when drained it, although got just a slight tinting - like VERY weak tea - when refilled and was getting air out of tank before restoring power).
Hoping amp meter shows at normal mail delivery time tomorrow.. but more and more, it seems when I order anything important to do with in home or firearms repair, it shows up after 5pm (lol, or it gets lost).

Thanks for help / answers. I haven't fingered up amps, watts, etc. since college!! In fact, I had to get a new multimeter since my old one died (Realistic from Radio Shack - was top of the line way back then! Lasted 30 years!) When I find out watts wrong, will report back.

You need to make sure that you have 220 or better at the two top screws of the upper thermostat.

Did you verify that ?

Also, did you verify you wired it correctly ? Better double check…..

 

[Twowaxhack]

As a diagnostic test when I don’t have any test meters but I’m pretty sure I have the correct voltage…..

Very temporary……


Bypass the thermostat and run 220 directly to the upper element screws.

Put your ear to the tank and if it’s heating, you’ll hear it.

If it works then, you either have it wired wrong or defective upper thermostat.

If it doesn’t work then you have the wrong voltage or a bad element.

Don’t electrocute yourself.

 

[MrMega]

I waited to meter to arrive, then didn't really need it. No draw on anything. Checked every single wire for continuity again, every thermostat tap for correctness.. all checked out then all hooked back up again. Leads from service show 249V but noticed my crimping looked a tad bit off and one wire a bit black... I snipped a bit off, cleaned the wires with Dremel then soldered. Hit it with power again and still cannot hear a *&^% thing. Hit eco switch for good measure and still nothing. Put all back together and gave up.
Came upstairs for something to eat and.. wth?! Warm water!!!!!!!! Already! (new elements are inches longer than what was in there)
Only thing I can possibly think of is, when guys came to switch out whatever was wrong with well pump, that was causing it to turn off, again and again, then must have put tool box on tank and pushed too hard on wires. Cannot think of anything else, for it to power it for just past a year, then up and fail.
So, re-crimped and soldered, so hopefully I am good to go.

THANKS to everyone for your answers! Going to be nice to wash hands in warm/hot water and not next to ice cold water... plus take a HOT bath tonight.