OK, I’m sure this is not the issue with yours, but I had the same thing. Turns out the water pressure in the house was so high that it forced hot water out of the relief valve and down the drain and there was no sign of it.
We only found it when the water company told us we had “a toilet leaking”, so I did the red dye thing and none were. I happened to go past the WH and felt the drain pipe from the pressure valve and it was hot, meaning we were losing hot water (*not to mention electricity) down the drain, which explained why the water was sometimes lukewarm-ish. I replaced the valve with a new one, and reset the pressure at the house-inlet, and the periodic fluctuation went away.
As I say, probably not your problem, seems a stretch to think it would happen to a lot of people, but there you go.
My gas hot water heater does not have an expansion tank. When cold water is heated it expands and pressure increases. Many older systems have a vertical pipe filled with air to deal with expansion. If not pressure relief valve on side of tank can release water.
Mine is near a floor drain but i have an aluminum pie pan under the relief pipe to indicate when this happens and especially if very much. So far only a few drops. Pan not filled.
I would think much depends on how much water you use. If you run out of hot water tank is filled with cold and pressure increase is highest. If only part filled might be much less problem. If its a problem, expansion tank (now required by some codes) or larger tank could be a solution.
Yes, that isn’t the issue in my case. The pressure release would dump water onto the basement floor.
Neither does my electric hybrid. I wonder if, since I am on a well, the well tank is serving that purpose. It certainly has a head of air (perhaps in a bladder?).
I have an expansion tank that looks exactly like that… but it is part of the oil-fired hot water baseboard heating system. Nothing on the domestic hot water.
Well, I suspect that they rely on a “trick” to avoid much of the warranty repairs.
Customer calling Rheem: “My hybrid HWH is beeping and not heating”
Rheem CS agent: “We’re really slammed now, so we can get to you in a 9 days from now”
Customer: “What??!!!??? How am I supposed to manage without hot water for 9 days???”
Rheem: “Press SETUP, click up, up, up, until you see “resistive heating only”, and select it.”
Customer: “So I need to turn off my heat pump part? That’ll cost me a lot more electricity!”
Rheem: “Those are your choices”
… 9 days go by …
Plumber for warranty arrives.
Turns on heat pump, and it starts heating the water.
Reports “no problem found”.
A week later it beeps again and refuses to heat the water in heat pump mode.
Customer calls Rheem and goes through the same thing again. This time, setting to resistive heating doesn’t work. And now there’s a 13 day wait for service (holiday season, you know).
Customer, in a fit of pique, drives to HomeDepotLowes, buys a new regular hot water heater and has it installed the next day.
No more warranty issues for Rheem.
What’s the “trick”? Well, not so much a trick as people not willing to go without hot water for a week or two while waiting for warranty service.
Funny you would say that. Mine is a Rheem. The app is called “EcoNet”, and yes I have called for service. The guy was here the next day. He’s the one who replaced the pressure relief valve, no charge.
As it turns out it wasn’t Rheem’s fault, the pressure in the pipe was almost 90. (We live in a hilly neighborhood, and we’re at the bottom of the hill so to get enough pressure to the top the utility runs everything at very high pressure.) Anyway, he replaced the pressure relief valve and went on his way.
When the same thing happened 6 months later we got a local plumber to replace the inlet pressure valve and run it down to about 60, and all has been well ever since.
But no we had no issue with Rheem, except he didn’t realize the valve had failed because of over-pressure, he just thought it was a bad valve.
We have no floor drain in our HVAC room, so the relief valve is piped all the way to an elevated drain, which also serves the geothermal HVAC detritus and drains to the river. We never see any of the waste water product, which is why um, we didn’t notice the problem until we were told by the utility that our water usage was so high.
LOL, I wan’t picking on Rheem per se. It’s just that I am looking for a replacement hybrid HWH and Rheem was the one I looked at most recently at Home Depot. The stores have very few choices of hybrid HWHs.
If I had to guess, in places where there are fewer people with hybrid water heaters (TN), and only a few qualified service people (they contract it all out), you might get better service than in a place with lots of hybrid water heaters (CA), and also only a few qualified service people.
Do you know how he did that? I wonder if it requires some sort of “vessel” or if it simply a matter of widening the pipe somehow (for same flow, a 3/4" pipe will have lower pressure than a 1/2" pipe, etc).
He had a water pressure meter (I also have one but never thought to use it. Had it for the RV to check campground pressure so it didn’t blow out the rig. $10 at WalMart).
And as Potter showed, it’s a bell shaped gizmo right where the water enters the house. He tried adjusting it there but it was frozen, having been in the same position since 1978, I assume. So he cut the old one out, put a new one in, and left it at 50psi.
Which was ridiculous, it felt like a trickle. So a couple days later I went downstairs and turned it up to 60, and left it there. Need an adjustable wrench and I think that’s all.
A little late to this thread, but I switched to a hybrid water heater several years ago. I estimate my power bill dropped by ~$25 a month, so saving about $300/yr. Mine has an 80 gallon tank, and operates exclusively in heat pump mode. It’s installed in the garage in FL, so there’s plenty of ambient heat for the heat pump to run effectively. I’ve never needed to turn on the resistive element.
The water heater has a controller screen, not unlike a thermostat. Mine has multiple operating modes:
ECO: heat pump only
Hybrid (heat pump and electric as needed)
Vacation mode (idle/low temp for X number of days)
etc.
Same here! I have never turned on the resistive heating on my 80 gallon hybrid HWH.
Of course, it is now acting up again with an almost constant alarm and not heating as it should. I really need to replace it, but I am not in the mood to pay $2500+ for a simple water heater (what a ripoff! Those things should be under $1000, it’s a simple tank, heat exchanger, and a tiny compressor, and one really simple circuit board). Plus, I’m not sure if I am strong enough to lug it into place to install it. Installing it is easy, would take me an hour or two as I already have flexible screw hoses for most connections except the condensate drain and the emergency pressure valve. Here are some photos -
So I bought mine for about 450 dollars. Yours is 2500 dollars. Jeff saves 300 dollars a year, I am assuming that is electrical because he said resistive. Mine is gas and costs about 120 dollars a year to run. So it takes Jeff 7 years for it to pay off and it would take me 17 years. I think I will just stick with natural gas.
what happens if you set to ECO and it gets too cold to adequately warm the water? Does it warn you somehow? Or just send you lukewarm water.
Obviously, it may get too cold at night but then work OK during the day, so can you tell this happened after the fact? So I assume you can bump up the temp to handle this?