I have this exact model, and I wish I didn’t. It turns out there’s a flaw in the logic that controls the heating elements. When in “Energy Saver” mode (the default mode), the lower heating element won’t heat the water. So when you start to use the hot water, as the hot water goes out, the replacement cold water coming in isn’t getting heated at the bottom. This drops the temperature of the existing hot water in the tank, and it takes several hours of no hot water use for the tank to get to your desired temp. For my family it means we get about 1 1/2 showers (showers last about 7 or 8 minutes) before the water starts coming out lukewarm. You can see this happening on your unit by activating the diagnostic mode on the panel and watching the lower element water temp.
I went several rounds with Rheem’s customer support (including have two separate techs come to my house to inspect it) before someone finally acknowledged in writing that there’s a known defect in the logic of the controller board. They tagged my unit as defective, but so far have not been able to replace it since they haven’t engineered a fix and started producing a new version of the water heater with said fix.
My advice, stay away from Rheem hybrid water heaters for a while until they get it sorted out. Also, pro tip: Keep it on the “High Demand” mode so that it’s always using electricity + heat pump to heat the water. That gives you the most aggressive heating profile and does not contain the flaw where the lower heater element won’t activate. This was the advice their engineer gave me, and it’s allowed us to have hot water for more than a shower or two.
This is interesting. Rheem used to be seen as a premium brand in Australia… I wonder if they’ve gone downhill.
Keep it on the “High Demand” mode so that it’s always using electricity + heat pump to heat the water.
How much more electricity does this use?
I don’t have historical data for the initial time period where I was trying to use this “normally” / using the default mode. However, here’s a screen shot of last month’s usage. Two adults in the house.
I was considering buying one so this is good to know. I wonder if AO Smith hybrid water heaters are any better.
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No expansion tank?
Guessing its a hybrid unit? I have a hybrid one by GE. Goddamn its loud.
Don’t forget to turn up the water temperature. Mine also was set to 120 by default, but that’s too cold. You need 135-140 or so, otherwise you’ll find that you run out of hot water pretty quickly, especially if you have people taking showers back to back, or running the dishwasher/washer while someones showering, etc.
What’s an expansion tank? I set it up like the old one was set up. All I did was disconnect the old one and reconnect the new one to the same pipes coming out of the wall.
An expansion tank is necessary for water heaters, because the process of heating water causes it to expand. Without an expansion tank, pressure could build to unsafe levels
All tanks are equipped with a safety release for the pressure and the only time when that delta in pressure can be problematic is when you go from completely cold to hot due to the higher amount of water that can fit in the tank at lower temp.
Otherwise I’ve never seen a house in Canada with an extension tank attached to the water heater and the water come in ice cold in the winter.
Pressure won’t build up, it will be let out by the pressure relief valve and make a mess on the floor. Which is also undesirable.
Well, right up until the pressure relief valve fails. Whether it fails open or closed, you’re gonna have a bad time, because either way you’re probably going to have a lot of water where there’s not supposed to be water.
If it’s necessary then how did my last tank make it 20 years without one?
If you are on municipal water and there is no check valve between you and the water meter then the municipal water supply is acting as the expansion tank. It may not be to code in your area but that’s how many homes were built in the past.
The expansion tank isn’t just for the water heater. That increased pressure puts undue strain on the entire plumbing system in your home. It will cause toilet fill valves to fail, supply lines to rupture, and possibly even pinhole leaks. A lot of plumbing issues are solved by installing an expansion tank.
Honestly, I don’t know, I’m not a plumber. There are a couple possibilities, including that it was built into the water heater or the relief valve did it’s thing. Some water heaters don’t need expansion tanks at all, either. It’s generally a “just in case” thing, since the right failures in the wrong way could lead to a hot water bomb going off in your house.
Yeah but that was like the coolest mythbusters episode ever /s
In reading it looks like it is for homes newer than 1986? Our old water heater was 20 years old and we never had any issues with the pressure getting too high.
Another comment here says the lower element of this unit has a flaw. Might look into that.
I’m not a plumber but that looks pretty clean! Good job. I’m hoping to upgrade to a hybrid electric water heater sometime in the future. Currently running on regular electric (boo!).
No drain pan for when it eventually pops? Rest looks good!
The drain pan thing seems to only be code in certain places. Over here they just need the foam block at the bottom.
While not not necessarily required by code, a drain pan + a leak sensor in the pan are useful in mitigating potential disasters.
Doesn’t have to be fancy either, they make smart leak sensors or basic ones that are just ear piercingly loud.
Was going to say, everything looks nice except missing drain pan, which I’m sure is code.
Different places have different codes. No pan on ours either.
It’s in a concrete garage, and a foam pad is recommended over a pan.
I’ve never seen the foam pad before. What purpose does it serve?
My last place had a drain pan (third floor condo) which makes sense to me. My new place it’s on a raised platform in the garage.
It provides thermal insulation since the tank is on a concrete slab.
No straps? Middle of the US somewhere?
They arrive Wednesday.
It’s not on a stand that elevates it off the floor either, nor does it have an expansion tank or drain pan, so I’m guessing it’s not in California.
Nice job! I have had the same unit for about 3 years now and I have been very happy with it. The amount of electricity it requires compared to a convention is a heck of a lot less. It also has the nice side effect of cooling and dehumidifying my garage during the summer time.
I was surprised how noticeable the cooling effect in the garage was. Granted it wasn’t that warm of a day but I’m curious what it will do on 90+ days.
You don’t need earthquake straps?
They arrive Wednesday
Wow this is a major undertaking!
120°F is too low for a water heater. 135°F is the minimum necessary to prevent bacteria growth inside the tank. And like the other person said, your hot water will last a lot longer with a higher temperature. Just don’t crank it too far beyond 140° so you don’t accidentally burn yourself.
120 is the lower limit for killing stuff off. Not much will live or grow at a sustained 120.
I leave mine at 120 and every Sunday it kicks up to 135 for an hour for peace of mind.
