On Sat, 23 Dec 2006 11:56:35 -0700, Ashton Crusher wrote:
You will not want to mess with swapping out elements when an emergency
That's for sure.
hits. First off the water will be hot so you'll have to do more then
Nope. If the water is hot, no need to swap elements.
Having said all that, elements are cheap, the simplest thing to do
would be as the sales guy suggested and just change the two elements
to 3000 watt ones. It will take longer to heat water but you'll have
Maybe the simplest, but then you live with a performance impediment all
the time.
I think the simplest would be to put in a switch or rewire the elements
ONLY DURING AN OUTAGE such that both elements run in series. This way
you get to heat your water, it takes an age, but when the power comes
back on you get the full performance again just by undoing your change.
No cost if you don't need a switch. And you don't have to deal with
doing an element swap during an outage or living with weak elements
during the other 99% of the time.
Given:
Watts=Amps*Volts
Volts=Ohms*Amps
If we use 240volt, 4800watt elements the math is nicer.
For a single element:
4800watts=Amps*240volt, Amps=20
240volts=Ohms*20amps, Ohms=12
Ohms are important, because they are the constant for a given heating
element. Amps and so watts will change if we change the voltage. (That
means your 5000w generator may be OK trying to run 5500w elements,
because the voltage will drop and the power will drop and it might be
fine.)
For two elements in series (2x the Ohms):
Watts=240v*240v/24ohms, Watts=2400.
So you get 1/2 the wattage when you run the two elements in series. For
your 5500watt elements, that means you get 2750watts. Nearly as good at
heating as 3000watt elements, but you get 5500watts when all is well.
This is MUCH better than using 120v on one element because you are using
both elements. With 120v and standard water heating wiring:
Watts=120v*120v/12ohms, Watts=1200 (or 1/4 the wattage).
sdb
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