# Electric HWT



## OldSchool (Jan 30, 2010)

Tell me whats wrong with this HWT 

We already solved the problem after three attempts ...

We got a call for no hot water ...

I sent a guy out to see what the problem was ...

This is what we found the first time ..

High limit reset was activated ...

we checked everything ...

We checked resistance of elements ... We checked the voltage at elements ... We tested current draw ... We checked the thermostats ...

Everything checked out .. And my guy changed thermostats except the high limit ..,

Worked good for several days and then again no hot water

Customer hit the reset and when I arrived there was hot water ... Again I go through all the steps and everything is the proper numbers ..

The third time I get a call a few days later and again off on reset ...

Again I perform the same test ... 

What do you think the problem was ... The tank keep going off on reset


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## RW Plumbing (Aug 16, 2010)

Wire short somewhere it touches the tank every so often and grounds out.


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## Gettinit (May 9, 2012)

Well, if the temperature was in fact too hot there may be three problems.

1. Bad high limit switch.
2. The wiper was stuck.
3. The homeowner wired it wrong and it kept power to the element until it tripped.


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## user2090 (Sep 26, 2009)

Original problem was a faulty stat. 

Additional problem was a faulty stat.

That has happened to me before. Had a run of stats one year that it seemed the whole batch we were shipped were funky at a high level.


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## bizzybeeplumbin (Jul 19, 2011)

tstat not touching the tank completely or pulled away.


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## OldSchool (Jan 30, 2010)

So far nobody got it


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## Gettinit (May 9, 2012)

OldSchool said:


> So far nobody got it


Good lord what kind of crap could it be?


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## OldSchool (Jan 30, 2010)

It a once in a million situation


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## user2090 (Sep 26, 2009)

The homeowner is dialing up the stats?


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## AWWGH (May 2, 2011)

OldSchool said:


> So far nobody got it


Incoming voltage problem? Low voltage spikes draw high amps and possibly causing trips?


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## OldSchool (Jan 30, 2010)

AWWGH said:


> Incoming voltage problem? Low voltage spikes draw high amps and possibly causing trips?


Nope


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## Tommy plumber (Feb 19, 2010)

Grounded heating element.


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## AWWGH (May 2, 2011)

OldSchool said:


> Nope


Is it something basic or a once in a lifetime thing?


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## UN1TED-WE-PLUMB (Oct 3, 2012)

I always check continuity between the tank and the t-stats and elements. Every so often you will find either an element grounded out or a short on a wire that will cause the high limit to trip. My vote is for a shorted element or wire.


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## OldSchool (Jan 30, 2010)

Actually the problem was the upper element ...

It would read normal for resistance ... It would actually draw the right current when the tstat was on ...

I found that when the stat was off it was actually drawing 1.4 amps ...

This is why the tank would over heat at night ... The element was actually heating the tank with close to 300 watts ...

Funny thing is the element had 19 ohms and it didn't read any resistance from element to ground ...

The crack in the element was just enough to draw a small amount off current when off but no sign that it was bad ...

So I pulled the element once i found it to be draw current when it was not suppose to ...

Found small little rip in outer shell...

Test new element and no more current draw when stat was off


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## The bear (Sep 27, 2012)

Is there a secondary source of heat that is overheating the water and causing HLC to go out. In Florida heat recovery off a/c will overheat water to water heater


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## OldSchool (Jan 30, 2010)

The bear said:


> Is there a secondary source of heat that is overheating the water and causing HLC to go out. In Florida heat recovery off a/c will overheat water to water heater


No ...

It was the bad element that was over heating the tank ...


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## The bear (Sep 27, 2012)

Just read your answer, very good job on your part finding the solution


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## deerslayer (Mar 29, 2012)

OldSchool said:


> Actually the problem was the upper element ...
> 
> It would read normal for resistance ... It would actually draw the right current when the tstat was on ...
> 
> ...




Ok forgive me if this is a stupid question but after the thermostat cuts the power how can the element draw current?


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## OldSchool (Jan 30, 2010)

deerslayer said:


> Ok forgive me if this is a stupid question but after the thermostat cuts the power how can the element draw current?


It's 240 ... Power is only stopped on one side


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## AWWGH (May 2, 2011)

OldSchool said:


> It's 240 ... Power is only stopped on one side


One side would still need a ground to semi-complete the cicuit..Right? Wouldn't the one pole still need a ground to do so?

When ohmed to the ground there was no continuity?


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## OldSchool (Jan 30, 2010)

AWWGH said:


> One side would still need a ground to semi-complete the cicuit..Right? Wouldn't the one pole still need a ground to do so?
> 
> When ohmed to the ground there was no continuity?


It would need a ground as you say ... Which is the water ...

I did test with wires off ... From one side of element to ground and then on the otherside and both read no continuity ...

That's what was stumping us ...

The break was so small that the resistance of the element read right ... Both across it and to ground ... It wouldn't blow the breaker either and the current draw was dead nuts while running ...

That's what I say 1 in a million ...

And all the time it was still heating the hot water tank all night long until it went off on limit


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## AWWGH (May 2, 2011)

OldSchool said:


> It would need a ground as you say ... Which is the water ...
> 
> I did test with wires off ... From one side of element to ground and then on the otherside and both read no continuity ...
> 
> ...


Analog or digital ohm meter? I always use analog to ohm, I can change my ohms to 100k ohms rather than 1, can sense even the slightest short to ground.


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## OldSchool (Jan 30, 2010)

AWWGH said:


> Analog or digital ohm meter? I always use analog to ohm, I can change my ohms to 100k ohms rather than 1, can sense even the slightest short to ground.


Digital ... You might have a point


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## HSI (Jun 3, 2011)

May be a bit primitive and you need to be careful when checking this way. I always disconnect one side of the element making sure the wire is clear from grounding and turn power on. Check loose wire with one side of voltage meter and the other side to tank. If you have 240 your good. 120 volts shows bad element.


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## mpot (Oct 2, 2012)

Awesome thread. Can I archive it somehow?


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## Gettinit (May 9, 2012)

AWWGH said:


> Analog or digital ohm meter? I always use analog to ohm, I can change my ohms to 100k ohms rather than 1, can sense even the slightest short to ground.


What, you too good to string light bulbs? :laughing:


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## plbgbiz (Aug 27, 2010)

mpot said:


> Awesome thread. Can I archive it somehow?


Subscribe to the thread and it will always be just one click away.


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