any electrictions here?

[earlbrown]

I'm looking to replace my leaky conventional water heater with a tankless....

While doing the research on current consumption .vs temperature rise .vs GPH I noticed I have a 30A breaker on my current unit.  Whats odd is that it has two 4500W elements.  At 246 volts I should be pulling more than 36 amps.

Are my heating elements prison raping the laws of thermodynamics, or does my beaker just not feel like conforming to society's wishes?

[gnonyx]

I believe when the tank is calling for heat the bottom heater elements is operating until the set temperature has meet, then the top heater element operates until that set temperature has meet, and not two will be on at the same time.
If you look at this site and punch in the voltage (mostly all is 240v) and then punch in the power (watts), press to Calculate and it will give you the current consumption.
http://www.ohmslawcalculator.com/ohms_law_calculator.php

I don't know which Tankless Water Heater you're looking into, but here are some if you want to look into.
http://www.rinnai.us/tankless-water-heater/

Consumer Reports on Tankless Water Heaters
http://www.consumerreports.org/cro/water-heaters/buying-guide.htm

[earlbrown]

I had a feeling it would only fire one element at a time. I just haven't looked at it to verify that.  Seems kinda dump to me with thermosiphonin g there would be no need to have a top element if you're only going to run one at a time.


The reason I noticed is I have to find out how many amps I have left in my service, then see what the temp rise would be with the biggest heater that will fit.  Since the water in GA drops down to 50s in winter I need about 50F in rise.  If I'm close I can always throttle back flow a little and/or build a surge tank to warm it to room temp before hitting the heater.


One day I will learn to replace something without having to make everything more better! 


EDIT:  Yep. The wiring is much more complicated that it appears it needs to be.  I'm going to have to dwell on this one for a while.  There has to be an advantage to the Rube Goldberg setup but I'm not seeing it at the moment.

http://waterheatertimer.org/How-to-wire-water-heater-thermostats.html

[daveismissing]

The two element design attempts to still give you hot water after your S.O. or children
have run the tank empty. Heating the top first allows you to come in and wash the grease
off your hands with hotish water after they have had 4 showers and 6 loads of laundry

[daveismissing]

I would have expected you to already run the water over the roof to pre-heat?
(maybe yours doesn't arrive at 50 deg )

[earlbrown]

The water on the roof heats the hottub!    (that's true BTW.LOL)



^that was during a coil replacement from a failed pump....


EDIT: If you look the white square in the middle is the roof heater. The lower square is the attached porch/greenhouse, and the top one is the H2O Nympho.   Turns out the Google van drove down my street a couple months ago. If you look closely you can see the GN in the carport.   What REALLY SUCKS ASS (and not in the good way) is I was outside walking to the Blazer when it rode by. If I would have noticed I could have staged some sort of messed up scene as I live on a dead end street and the fan had to ride back by!

https://maps.google.com/maps?q=101+shady+oak+dr+lagrange+ga&ll=33.01133,-85.130427&spn=0.000629,0.001206&oe=utf-8&client=firefox-a&hnear=101+Shady+Oak+Dr,+LaGrange,+Troup,+Georgia+30240&gl=us&t=h&z=20

[daveismissing]

Unfortunately (or fortunately) Googs did another recent drive by- up to that point a friend had his buttcrack displayed as he mixed compound outside while renovating another friends house 

[daveismissing]

Maybe you just need to use old radiator cores on the roof Earl

[earlbrown]

Oh god, I'd have a million dollars in T fittings!!    I thought about gathering up as many refrigerator condensers as possible and soldering the together.   The irrigation hose was a proof of concept. It also helped that 500 feet of it was only $45     Now that I know the sun can heat things, I'll do it right and use copper with alum flashing when I get an extra 3 or 4 hundred to spare.  Right now my monies are allocated to trying to get my pistons off the ground  (and fixing my damn hot water heater)

Anybody need a timing cover?  LOL