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Anyone familiar with Rheem smart waterheaters?
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electromotive:
I've got a basic (but brand new) Rheem water heater. It seems to me that there isn't much difference between it and a network enabled smart heater (i.e. I could pick up a few parts on ebay and add a lot of functionality). By chance, do any of you fine ladies and gents have the *smart* version?

This control box (over the topmost element) and a small bit of wiring seem to be the only difference, but I need to find someone that has one so I can verify the wiring behind this controller:

ajb:
As with most things like this, the hardware is the easy part, and as you surmise, is probably pretty darn simple.  The trick is that with a bit of carelessness/design oversight, it would be very easy for whatever software runs the thing to cause trouble ranging from wasting a bunch of energy to creating enormous mess, or possibly even structural damage to your house if the relief valve isn't set up properly. 

Best to leave the existing electromechanical thermostats (there are usually separate thermostats for the top and bottom heaters) and thermal cutouts in place as a last line of defense, and add your controller in between the supply and the existing appliance wiring (maybe bring out the two heaters separately, you could probably improve performance a bit by controlling them independently).  You can set the existing thermostats to a relatively high (but still safe) temperature, and then use your controller to reduce the temperature by turning the whole appliance supply on and off if that's what you're after.  That way the worst case scenario is that your water heater runs hot and wastes energy.
IDEngineer:
Slightly off topic: Almost all of the energy consumed by a natgas water heater goes to actually heating the water. Ever notice that virtually all gas appliances have spark igniters now - except water heaters? It's because even the pilot flame helps keep the water warm, unlike virtually all other pilot flames where their heat is basically 100% waste.

Every appliance in my house that can be natgas fired IS natgas fired. My electrical power goes out many times a year, but I literally cannot remember a natgas "outage" in my entire lifetime and I've lived in four states, multiple homes in each, in widely varying climates. That's decades of uninterrupted natgas service. Put as much on natgas as possible, switch to LED bulbs, and you can run your entire house on a relatively small generator when the power goes out. All-electric homes cannot do that because there's several kilowatts in the water heater... several more in the oven and cooktop... several more in the furnace or baseboards... etc.

Maybe you're using an electric water heater because you don't have an option. But if you DO have an option, gas (natural or propane) is the way to go. You'll have hot water no matter what the electric company does.

EDIT: Being completely objective, one downside to gas water heaters is their thermal hysteresis. The water temperature can vary by 10-20 degrees as a consequence of the design of the thermocouple+valve design that doesn't require external power. Thus I try to take my shower after someone else does, so the water heater has kicked on and is headed for the top of its hysteresis range.  ;D  I don't know if electric water heaters have tighter temperature regulation, or if there's anything but bang-bang style controls on their heating elements. I haven't been able to find an off-the-shelf cooking oven with linear control of its heating elements so I doubt water heaters are any better.

Sorry for the distraction, just a "favorite cause" of mine. We return you to our regularly scheduled programming....  :)
electromotive:
Natgas would be nice, but there's a weird sort of situation going on. About 20 years ago, a company called Horizon came through and planted new yellow plastic gas lines all over creation. Before that, you had your choice between three different truck loaded/offloaded suppliers. Long story short, Horizon went bust -- the lines are there, but they aren't in use. If you live in the city (I don't) a company called Columbia Gas (I'm in the U.S. -- weird name, I know) has lines everywhere. Didn't matter though -- they never got close to where I life. However, when Horizon went bust, they all became greedy. My home is total electric, and it's cheaper to run everything on electricity than it is for my parents to run their home on a combination of gas (range, furnace) and electric (water heater).

We're planning on adding some energy diversity soon in the form of whole-home generation and a solar array with Tesla-style backup.
IDEngineer:

--- Quote from: electromotive on March 05, 2019, 09:39:30 pm ---Long story short, Horizon went bust -- the lines are there, but they aren't in use.
--- End quote ---
Sounds like the dark fiber situation after the .COM bust in the early 2000's. Players laid cable everywhere, then went under. Other companies picked up the infrastructure for pennies on the dollar and started renting/leasing it out to other companies without hooking anything up to it at all. Just renting dark glass in the ground.


--- Quote ---a company called Columbia Gas (I'm in the U.S. -- weird name, I know)
--- End quote ---
Not weird at all! Here in the Pacific Northwest every fourth company has "Columbia" in its name. The largest river drainage in the region is the Columbia River. And so forth. And as every schoolchild knows, "Hail Columbia" is the official "Song of the Vice President of the United States".  :)
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