Electric water heater question

[Paso One]

On a GSW electric water heater that has two 4500 watt elements.

Both elements when the power is on shows full voltage when probed with the volt meter. 200

When I pull one wire off the element and turn to the ohm meter scale and probe the element I get a reading the same as I get doing the same procedure on the new element.

I assume that means the element is good since its the same reading as a known new element.

What is causing the element to not heat the water.???

Is there a anothe test I can do??

Both reset buttons are pushed in.

[maintenanceguy]

Having voltage at the element does not mean that electric current is going through the element.

You can measure voltage at a light bulb socket but no electricity will flow unless the bulb is screwed in so it can pass through the filament of the bulb.

Two ways to test the elements:

1) With a current meter, clamp the current probe around one of the element wires and measure the electric current traveling through the current. I prefer this method since I don't have to unhook anything.

2) If you don't have a current meter (the amp setting of a meter that reads miliamps doesn't count), you can measure the resistance of the element. Turn of the power, remove one wire from the element and measure the resistance from terminal screw to terminal screw. For a 4500W element that runs at 240V, the resistance should be around 19 ohms. If it's a lot higher or infinite, you have an open element that's not letting electric through. If it's much lower, you have a shorted element.

Electric kills, turn it off before testing and if you're not sure of the definitions of current, voltage, resistance, ohms, amps, call somebody. I'm very much in favor of people doing things for themselves but don't take a chance on getting hurt.

[Paso One]

Found the problem One leg of the power coming in overhead to the building Blew the insulink

[Paso One]

Thanks Maintenance guy we wer both typing at the same time I see both times are 5:12
Thanks for your detailed post.

I did have 19 ohms so you were bang on.

I was tracing back to the breaker when I tested one terminal I had 118 volts the othe screw had 86 volts.

So I assume it was back feeding.

I did not have my clamp meter I was working with a little Radio shack voltmeter that was in the back room.

Thanks for the warning I'm one of those guys that only knows enough to be dangerous But I am very respectful and do know better than basics. :)

Thanks again for your answer.

I did not know the 4500 watt should have 19 OHMS resistance

I had a spare 3000 watt element and it had 22 ohms which I guess is correct for that element ???

[hj]

Given the cause of the problem, your original statement that both elements had "full power" had to be incorrect thus making it impossible for us to have given a diagnosis. In fact there is no time when "BOTH elements" have full power in a properly functioning domestic water heater.

[Paso One]

Yes my statement was not correct full power at both elements.

When I attached the meter it went over 200 and I went on to something else.

One leg had 118 and the other leg had 86 (Back feeding )

This particular water heater is wired for both elements operational at the same time.

I realize most electric water heaters don't have both elements running at the same time.

It has been working for the last 5 years wired for both at the same time.

It is used in a radiant floor heat application.

Thanks for all your help.