# Water Heater Pulls 18A But Water is Cold??



## swimmer (Mar 19, 2011)

This 1 year old Whirlpool electric water heater pulled 18 amps all the time even if no water tap was on. The customer's power bill has been high since about 2 months after it was installed. 18A were seen on both the black and red wires. There is no neutral. 

So how can it possibly be pulling all this current without heating water?
I also must be missing something on the attached schematic. To me, it looks like the top and bottom heating elements cannot be on at the same time due to the upper thermostat.

Anyway, I replaced the faulty breaker feeding the water heater (one pole was not conducting), corrected the DIY wiring (#12 romex in flex without a flex connector) and referred the customer to a plumber.


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## telsa (May 22, 2015)

swimmer said:


> *This 1 year old Whirlpool electric water heater pulled 18 amps all the time even if no water tap was on.* The customer's power bill has been high since about 2 months after it was installed. 18A were seen on both the black and red wires. There is no neutral.
> 
> So how can it possibly be pulling all this current without heating water?
> I also must be missing something on the attached schematic. To me, it looks like the top and bottom heating elements cannot be on at the same time due to the upper thermostat.
> ...


*
This is an apparent reading. Don't be so sure.*

A two-pole breaker with a blown pole -- creates an RL circuit within the hot water heater.

IE you're reading a 'solenoid' demand for AC current.

No actual power should've passed. Instead, you've been reading the RL circuit pumping voltage in and out... of 'the coil.'

Get it ?

It does not matter that the water heater is a lousy AC solenoid.

It's sufficient that the heater is draining current via hysteresis losses.

https://en.wikipedia.org/wiki/Hysteresis

You'll be reading crazy-high _apparent_ current flow, while the actual power transmitted is pathetic.

Get it ?


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## MechanicalDVR (Dec 29, 2007)

It's typical for only one element to run at a time. Did you ohm out the elements? The only plumbing problem I could see is if the lines are connected backwards and hot is pulling off the bottom of the tank.


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## Dennis Alwon (May 9, 2009)

You probably have a blown element and it is just leaking thru the water causing the current draw. 

If they are getting some water but not alot then I suspect a bad thermostat or bottom element is bad. See if you have 240V across the element


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## PlugsAndLights (Jan 19, 2016)

My first guess is the top burner isn't operating. Pulling the covers and 
checking things with a meter would be a good start. Possibly the top 
thermostat is stuck in the position that sends the power to the bottom 
thermostat. Is the water actually cold or just not as hot as it should be? 
And regarding the bottom element not being able to operate when top 
is on; that's normal. 
P&L


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## MechanicalDVR (Dec 29, 2007)

Dennis Alwon said:


> You probably have a blown element and it is just leaking thru the water causing the current draw.
> 
> If they are getting some water but not alot then I suspect a bad thermostat or bottom element is bad. See if you have 240V across the element


A voltage reading across a blown element will still show 240v, just like an open single switch will show line voltage.

A water heater must be troubleshot in a single phase condition to verify continuity.


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## PlugsAndLights (Jan 19, 2016)

Keep in mind that 18A is the expected draw.
P&L


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## swimmer (Mar 19, 2011)

The water may be heating up to a little cooler than luke warm but I'm not sure. Note that I replaced the breaker and measured 240V at the water heater input. I made some ohm measurements with power off as described in the manual and they checked out nominal but I forgot what I was measuring. If I go back there, I'll try to measure voltage across the elements. Access in the closet is tight. It seems I should be able to ohm the elements if I can access them.


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## MechanicalDVR (Dec 29, 2007)

swimmer said:


> The water may be heating up to a little cooler than luke warm but I'm not sure. Note that I replaced the breaker and measured 240V at the water heater input. I made some ohm measurements with power off as described in the manual and they checked out nominal but I forgot what I was measuring. If I go back there, I'll try to measure voltage across the elements. Access in the closet is tight. It seems I should be able to ohm the elements if I can access them.


Voltage across an element proves nothing, the wires removed from the element would give you the same reading.


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## PlugsAndLights (Jan 19, 2016)

Check for normal operation which is:
-top thermostat sends power to top element until thermostat is satisfied
-once satisfied the top thermostat sends power to bottom thermostat
-bottom thermostat sends power (from top therm) to element until 
thermostat is satisfied at which time thermostat opens and no current 
flows to either element 

All there is to check is the 2 therms and 2 elements. Note that changing
the heat setting of each therm is quicker than waiting for the water temp 
to otherwise trigger calls for heat and satisfied conditions. 
P&L


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## Bird dog (Oct 27, 2015)

When you go back if you can take top and bottom thermodisc thermostats with you b/c they can be adjusted low enough to turn on and off. Secondly, with the power off disconnect one side of each element and check its resistance. IIRC it should be about 10 ohms. Both sides of the element should be open to ground.


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## LGLS (Nov 10, 2007)

Just a sidebar here aside from the WHs diagnostic problems... Swimmer, your location says California - I'm curious as to what the customer's KWH rate is for electricity and why one would opt for the most expensive way to cook water known on the planet.


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## macmikeman (Jan 23, 2007)

You have to lift one wire off each element, then test between the lifted conductor to the now empty screw of the element for 240 volts. If it is blown you wont read the full voltage.


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## just the cowboy (Sep 4, 2013)

*Pull a element*

If all else fails to show something wrong, pull a element and look to see if it is covered in scale. 1 year old I would not think so, but i have seen older units so covered it would not heat water but draw full current.


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## MechanicalDVR (Dec 29, 2007)

just the cowboy said:


> If all else fails to show something wrong, pull a element and look to see if it is covered in scale. 1 year old I would not think so, but i have seen older units so covered it would not heat water but draw full current.


I've had them so scaled up I had to clamp on a vise grip and pry them out of the tank. With the right water chemistry it doesn't take long.


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## frenchelectrican (Mar 15, 2007)

MechanicalDVR said:


> I've had them so scaled up I had to clamp on a vise grip and pry them out of the tank. With the right water chemistry it doesn't take long.


Yep I know with some hard water do that and oversalted watersofter do the same thing. 

and most common curpit is most home owner never bother to drain the gunk out the tank once a while. That I useally do it once a month if not used alot so that is a good way to get some of scale or crap out.


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## Dennis Alwon (May 9, 2009)

MechanicalDVR said:


> Voltage across an element proves nothing, the wires removed from the element would give you the same reading.


Yes but that was not my point. If it were the element I was checking I would either disconnect everything and oh, it or I would disconnect one side and see if I had voltage on the other side.


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## MechanicalDVR (Dec 29, 2007)

Dennis Alwon said:


> Yes but that was not my point. If it were the element I was checking I would either disconnect everything and oh, it or I would disconnect one side and see if I had voltage on the other side.


It's all in the wording my friend, I'm guilty of this myself at times.


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## LGLS (Nov 10, 2007)

just the cowboy said:


> If all else fails to show something wrong, pull a element and look to see if it is covered in scale. 1 year old I would not think so, but i have seen older units so covered it would not heat water but draw full current.


I'm not buying the scale covered element story as believable. A submersed element, even covered with scale, is still going to heat the water. Unless you can explain where all that heat is going.


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## just the cowboy (Sep 4, 2013)

LawnGuyLandSparky said:


> I'm not buying the scale covered element story as believable. A submersed element, even covered with scale, is still going to heat the water. Unless you can explain where all that heat is going.


I have seen then the size of the hole that it goes thru. It becomes like a concrete encased element that the heat don't radiate correct.


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## Semi-Ret Electrician (Nov 10, 2011)

Calcium buildup in a WH is very common in AL. 

If an element is covered with scale heat won't be transferred to the water.

Even on a new WH I replace the angled drain valve with a full ported ball valve and hose connection. Once a year hook a hose to it and let it run until it runs clear.
If it's plugged, it's easy to rod it out, with a coat hanger.

I've gone 10 years, and still counting, without a problem.


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## MCasey (Dec 7, 2016)

LawnGuyLandSparky said:


> I'm not buying the scale covered element story as believable. A submersed element, even covered with scale, is still going to heat the water. Unless you can explain where all that heat is going.


Calcium or lime build up and the air entrained in it will insulate the element well and inhibit heat transfer. In a coil type heat exchanger a thin coating of scale will reduce performance significantly.


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## swimmer (Mar 19, 2011)

LawnGuyLandSparky said:


> Just a sidebar here aside from the WHs diagnostic problems... Swimmer, your location says California - I'm curious as to what the customer's KWH rate is for electricity and why one would opt for the most expensive way to cook water known on the planet.


These condos / apartments were built in the 1970s. I guess power was cheap then or natural gas was expensive because they don't have gas.
My KWH rate is $0.08304 for delivery charges and $0.06919 for generation charges so I guess my total rate is $0.15223 per kilowatt-hour.
18A*240V*24*30 = 3,110,400 watt-hours / month = 3110.4 KW-H / month
$0.15223 * 3110.4KW-H = $473.50 per month.
She said she had big power bills.

On another tangent, this is a Navy town and a lot of sailors cart electric cloths dryers across the country when they get stationed here. Then they have to pay to get a dryer circuit (most newer homes are gas) and pay the high electric bill. Seems stupid that washer / dryers are not tied to real estate as "fixtures". I guess I shouldn't complain. I get a lot of work from this situation.


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## Southeast Power (Jan 18, 2009)

swimmer said:


> This 1 year old Whirlpool electric water heater pulled 18 amps all the time even if no water tap was on. The customer's power bill has been high since about 2 months after it was installed. 18A were seen on both the black and red wires. There is no neutral.
> 
> So how can it possibly be pulling all this current without heating water?
> I also must be missing something on the attached schematic. To me, it looks like the top and bottom heating elements cannot be on at the same time due to the upper thermostat.
> ...


element blown open ?


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## Southeast Power (Jan 18, 2009)

telsa said:


> *
> This is an apparent reading. Don't be so sure.*
> 
> A two-pole breaker with a blown pole -- creates an RL circuit within the hot water heater.
> ...


Odd and unhelpful comment. :blink:


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## MCasey (Dec 7, 2016)

Suncoast Power said:


> Odd and unhelpful comment. :blink:


Yet, theoretically accurate.


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## Big John (May 23, 2010)

I'm leaning towards current flow through the water. To be honest, I don't really think that's what's happening but the reason I don't like the calcified element idea is I would expect it to burn open: When it can't transfer heat it would be no different than running the element in a dry tank.


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## Galt (Sep 11, 2013)

Electricians looking for an electrical answer. a 240 volt water heater with 4500 watt elements will draw about 18 amps. Don't ignore plumbing problems. Are there valves in the lines so you can isolate the w.h. It don't take a very big leak to make a w.h. run continuously . Are there mixing valves on the toilets? These can siphon hot water back thru the cold side also a utility faucet with a hose on it and a spray nozzle and the valves left open can also siphon hot back to the cold side.


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## Galt (Sep 11, 2013)

just the cowboy said:


> I have seen then the size of the hole that it goes thru. It becomes like a concrete encased element that the heat don't radiate correct.


The heat does not have a choice it has to heat the water or overheat the element itself and burn it out. there is no place for the heat to go it can't simply disappear.


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## Big John (May 23, 2010)

Galt said:


> ...Are there valves in the lines so you can isolate the w.h. It don't take a very big leak to make a w.h. run continuously....


 Good thinking. I'd start there.


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## inetdog (Apr 13, 2016)

It seems to me that either the current and voltage are going into the unit and the heat is somehow being conducted away without heating the water or the current is flowing through some sort of fault and generating the heat somewhere else.

Sent from my XT1585 using Tapatalk


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## hardworkingstiff (Jan 22, 2007)

I bet this sounds silly, but ... the T-Stat is set correctly, right?


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## MechanicalDVR (Dec 29, 2007)

swimmer said:


> This 1 year old Whirlpool electric water heater pulled 18 amps all the time even if no water tap was on. The customer's power bill has been high since about 2 months after it was installed. 18A were seen on both the black and red wires. There is no neutral.
> 
> So how can it possibly be pulling all this current without heating water?
> I also must be missing something on the attached schematic. To me, it looks like the top and bottom heating elements cannot be on at the same time due to the upper thermostat.
> ...


For simpler reading purposes.


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## Semi-Ret Electrician (Nov 10, 2011)

Galt said:


> The heat does not have a choice it has to heat the water or overheat the element itself and burn it out. there is no place for the heat to go it can't simply disappear.


I've seen the bottom element completely encased in a bushel of calcium, a near perfect insulator. Yet the element survived.

Also, simply touching the hot pipe leaving the heater, with no users turned on could indicate a leak.


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