On Fri, 15 Aug 2003 02:28:49 GMT, (Doug Miller)
wrote:

In article , "Bob" wrote:
When I say "only one is on at a time" , I mean only one element in an
electric water heater is on at any given time. This I am sure of.

It's been a long time since I've had an electric water heater in a house I've
owned, so I could be wrong, but I don't think that's correct.


That is so. It heats the one end first (the top IIRC), then the other
end when it reaches temperature.

The label states "maximum allowable rating" and states "240V" with 2 "3000
watt elements factory installed"

And I agree..it will heat up alot faster (4 times faster) with 240v vice
120v but is the only reason it would be hooked up to 120v is that the
installer didn't have a clue?

For the third time, YES. The installer was incompetent. It's *supposed* to be
connected to a 240V source. Think about it, man: you said yourself that the
recovery time is 4 or 5 hours. That's absurdly long, even for an electric
water heater. Doesn't that tell you that something is *wrong* ? What possible
reason could there be for doing that deliberately? Why would anyone *want* to
wait five hours for the water to warm up again?


"Doug Miller" wrote in message
gy.com...
In article , "Bob"
wrote:
I did measure across the 2 input wires at the upper limit switch on the
water heater (it's a 2 wire system) and did read 120v.

I am pretty sure the wire is 10 guage but I will verify that.

The elements are 3000 watt and read 20 ohms. By my calculation (it's been
awhile but i think I remember) 240 volts across 20 ohms is just under
3000
watts (2880) and since only one is on at a time.....the math works out.

Yep. But what do you mean "since only one is on at a time" ?


On the side of the heater it does state 240v but I believe this to be a
maximum applied voltage only.

No, that means it's supposed to be connected to a 240V source, not 120V.


As I said the water is fine once it is heated up but if I do use it
up...it
takes much of the day to get it back....estimate 4 to 5 hours. This
doesn't
happen very often since there are only 2 people living here most of the
time.

It'll heat up a *lot* faster if it's connected to the correct source.

I am not sure if there would be any reason to hook up 120 vice 240. It
works
obviously other than the recovery time. Any ideas other than installation
error? It was installed 2 years before we moved in, which was 2 years
ago.

Obviously an installation error -- whoever installed it had no clue what
he
was doing.

So to recap, If I do revert to 240v the wire size must be 10 guage and
there
must be 30 amp fuses?

240V across 20 ohms is a current of 12 amps. But you have two elements,
hence
24 amps total. Therefore, yes, you need 10ga wire and 30 amp fuses or
breakers.


--
Regards,
Doug Miller (alphageek-at-milmac-dot-com)