Replace 120v element with 220v element

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DVOM

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I bought a 120v Whirlpool 19 gallon electric water heater as that was the only voltage I could find. The wiring going to the heater is 220v. About 19 yrs ago I had bought a Ruud water heater and switched the 120v element for a 220v element and it worked fine.

Now everyone I talk to, the water heater people, the plumbing supply people and the guy at the hardware store all are completely unable to tell me why this would be a problem. No one could give me a concrete answer to whether this is possible or a good idea. One told me there would probably be a problem with the thermostat. However looking for thermostats online, none are rated for volts or wattage so I'm guessing that's not a problem.

So my question is can I just switch out the 120v element with a 220v element? Is there anything else that would need to be done?

Thanks in advance.
 

hj

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YOU would need to change the thermostat, because one for 120 v. only breaks one feed if the ECO is activated and for 240v BOTH leads have to go through the ECO, (the thing with the red button). This assumes you actually are using 240 v. Using a 240 v element with 120v reduces its output by 50 %.
 

DonL

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Why not just wire it for the correct voltage ?

The tank may not handle the extra (2X) BTU rating very well. It will for sure be out of warranty, and insurance void.

Good Luck.
 

Dana

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YOU would need to change the thermostat, because one for 120 v. only breaks one feed if the ECO is activated and for 240v BOTH leads have to go through the ECO, (the thing with the red button). This assumes you actually are using 240 v. Using a 240 v element with 120v reduces its output by 50 %.

Power is relative to the square of the voltage, so the output at 120V will be 1/4 that of it's labeled wattage at 240V, a 75% reduction in output, not 50%.
 

Reach4

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Amperage is constant, so 1/2 the voltage will yield 1/2 the wattage, which is why a 4500 watt 240 element operated at 208 is only about 3800 watts.
That 4500 watt 240 volt element would be 12.8 ohms.
So at 208 volts, you would get 3380 watts (power= voltage squared/resistance) if the resistance stayed the same. But since the resistance rises with temperature, that same element would give a little more than 3380 watts. But not 3800.

If the 240 element was replaced with a 120 volt element and then powered by 120 volts, to get the same current, the resistance of the new element would be half as much as the 240 volt element. So the power would be half at 120 with the new element.
 
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hj

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It will last a lot longer, because the watt density is lower. When I needed 480v elements for a three phase heater, and all six were burned out, I used six 240v elements and wired pairs of them is series until the new ones arrived.
 

DonL

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It will last a lot longer, because the watt density is lower. When I needed 480v elements for a three phase heater, and all six were burned out, I used six 240v elements and wired pairs of them is series until the new ones arrived.

I have done strange things when I was in a bind also.

The thing about water heating elements, Is that the resistance changes depending on water temperature. So does BTU output.

You can see this, if you have a amp probe.

Those small water heaters are only rated for 120V for a reason. Safety comes to mind.
 

Ballvalve

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I have modified a $200 30 gallon water heater to operate both new 3800 watt elements independently. It has heated a 2000' house with radiant heat for many years. Beats a commercial rig for $2,000.

At first I fried many 4500 watt elements due to the high calcium in the water. I turned down the temp. and lowered the wattage. Now it runs longer, but elements last 3+ years. I suppose I have stopped cooking the calcium onto the elements.

interesting part is that this rig is prior to and inline with a big Polaris condensing propane water heater. I gave up on the issues with that unit and now it serves as a nice holding tank. Originally the electric one was just for backup and when propane was almost $4.00 a gallon.
 

Ballvalve

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YOU would need to change the thermostat, because one for 120 v. only breaks one feed if the ECO is activated and for 240v BOTH leads have to go through the ECO, (the thing with the red button). This assumes you actually are using 240 v. Using a 240 v element with 120v reduces its output by 50 %.

Seems like the 120v heaters use the 240v switches because they work the same and are a commodity item. No need to set up a line to build a single pole switch when a double won't hurt.
 

hj

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quote; Those small water heaters are only rated for 120V for a reason.

120 heaters use a single pole thermostat and ECO switch to ensure that the neutral is NOT wired though a switch. They can be ordered in other voltages, and wattages, but not 3 phase.
 

Ballvalve

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quote; Those small water heaters are only rated for 120V for a reason.

120 heaters use a single pole thermostat and ECO switch to ensure that the neutral is NOT wired though a switch. They can be ordered in other voltages, and wattages, but not 3 phase.

And why on earth not run a neutral through a 2 pole switch in a water heater? I have a 120v water heater and would confidently put in a 240 volt water heater thermostat. In my experience, a lot of neutral wires turn out to be the hot. Surprise!
 

Jadnashua

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And why on earth not run a neutral through a 2 pole switch in a water heater? I have a 120v water heater and would confidently put in a 240 volt water heater thermostat. In my experience, a lot of neutral wires turn out to be the hot. Surprise!
For the same reason light switches only have one pole...if it is installed properly, it doesn't matter, and it's less expensive.
 
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