Rheem Hybrid water heater changing operating modes on its own.

dean8j

I have a Rheem hybrid water heater model xe50t10h45uo. I live in Minnesota and run it in heat pump only mode for 2/3 of the year and electric only mode through the winter. This winter it has been it has been changing from electric only mode to Heat pump only mode on its own. Which cools my basement and removes the humidity which I don't want in the winter. Does this about every 2-3 days. I figure it must be some type of default setting and there must be a way to override it so that it stays in the setting I want it to be on or lengthen the amount of time before it defaults back to the Heat pump only setting.

Installed 12/08/22 in a heated basement.
The "Geofencing (home / away)" is disabled on the app.
The "scheduled away/vacation" is not being used in the app.
I have the "Follow Schedule" feature in the app turned off.
There are no alarms or alerts on the app nor on the water heater control screen.
It did not do this last winter.
There was an app update this year 2023.


My previous hybrid water heater had a way for me to override this feature. If I remember correctly I had to hold 2 buttons down, then go to something like number 8 & hit enter, then change the next number to the maximum & hit enter. That process changed the amount of days until it would default back to it's heat pump mode. Changed it from 2 days to three months or something like that.

Hopefully this makes sense.

Any help would be appreciated, thanks.

Jamie Hall

There was an app update this year 2023." Someone out in la la land thinks they know better than you...

ethicalpaul

I can’t compare mine with yours because I leave mine on Heat Pump Only all the time.

It doesn’t cool off your basement or dry it out in any measurable way.

in fact you’ll notice it creates no condensation at all in the winter because there’s no extra water in the air anyway 

Hot_water_fan

I think their winter (and even summer) dehumidification capabilities are greatly overstated - if you use 50G a day at a 100F delta T, that’s 41700 Btu. With a COP of 4, 30,000btu comes from the air. Whatever the fraction of that comes from dehumidification, it’s probably a rounding error. Would love to see someone measure it for a winter week or so. 

WMno57

ethicalpaul said:

It doesn’t cool off your basement or dry it out in any measurable way.

This is why I leave my basement windows cracked open a smidge all winter. That doesn't cool off my basement in any measurable way either.
I should probably get better at measuring though.

MikeAmann

AI is taking over and deciding for you how your water heater will be used.
You don't get to make those kinds of choices anymore because the computer now sees you as a stupid human. Next, you will become a virus and AI will eliminate you to protect itself.

ethicalpaul

WMno57 said:

ethicalpaul said:

It doesn’t cool off your basement or dry it out in any measurable way.

This is why I leave my basement windows cracked open a smidge all winter. That doesn't cool off my basement in any measurable way either.
I should probably get better at measuring though.

I've tried to explain this in the past, and people seem to purposely refuse to think about what I say, but I'll try it again.

Your basement is losing a lot of heat. Every wall, every window, is losing a lot of heat. Whether you have a heat pump down there or not, a lot of heat is leaving. Now what happens is the heat pump grabs some of that heat, which was going to be lost anyway, and puts it into its tank.

And by the way, your atmospheric water heater is pulling $h!t-tons of heat right up the flue 24/7 which you can close off if you exchange it for a heat pump water heater, but no one seems to remember that.

SallyM

Thanks for your post. We are having the same problem. Unit switches from Electric back to Energy Saver mode after a few days. I can't find any information specific to this issue in the Use and Care Manual that came with the water heater. I have sent a support request to Rheem. Will post reply if there is one.

Update (2/1/24): Haven't received an answer from Rheem tech support yet, but I found the attached FAQ on the Rheem website. Highlighted section on page 6 states:

Can you put the HPWH into electric only manually?

Yes you can; but only for a short time. The software programming wants the machine to run in an energy efficient mode. After about 2 weeks in the Electric Element Only mode, the software will attempt to go to Normal mode so it can be more energy efficient. If it does, you will see the mode indicator light on the user control change from Electric Heat only to Normal.

Italics are in the document. The switching back to Energy Saver mode from Electric is a deliberate design decision, although we -- like the original poster -- are seeing an interval of only a couple days, not the 2 weeks stated in the document.

Still hoping to get a reply from Technical Support. I would use the opportunity to explain how in the winter, and with our PV system, Electric-only mode is more efficient than putting an added load on our gas-fired furnace. The heat has to come from somewhere, and in this case the software is effectively turning our electric water heater back into a gas one.

SuperTech

If I remember correctly we found out on another thread on here last year that most of the heat pump water heater manufacturers designed their products so you cannot really run on heat pump only mode. The water heater will energize the resistance heating elements to recover from a setback. The manufacturers decided that higher customer electric bills was less important than customers complaining about running out of hot water from their fancy new heat pump water heaters. 

ethicalpaul

I have been running on heat-pump only mode for years. It has never switched itself off of that mode.

There was a person who was powering off his heater over and over and yes when you first power it up, it will use the electrical resistance heater to bring it up to a certain level. This freaked out this person, but the answer was "don't keep powering down your water heater".

I think this person for a misguided reason, wants to keep their unit on resistance-heating mode only. I would just let the device do what it wants if I were this person. If you want a resistive electric heater, get one instead.

Or if you want a gas or oil one for some weird reason, get that one. The government isn't going to take them away.

SuperTech

ethicalpaul said:

I have been running on heat-pump only mode for years. It has never switched itself off of that mode. There was a person who was powering off his heater over and over and yes when you first power it up, it will use the electrical resistance heater to bring it up to a certain level. This freaked out this person, but the answer was "don't keep powering down your water heater". I think this person for a misguided reason, wants to keep their unit on resistance-heating mode only. I would just let the device do what it wants if I were this person. If you want a resistive electric heater, get one instead. Or if you want a gas or oil one for some weird reason, get that one. The government isn't going to take them away.

Actually I have heard that fuel burning water heaters are the next target of states like California and New York. 

ethicalpaul

OK give me $100 today and I'll give you $200 when I can no longer buy a gas water heater at Lowe's in NY

Larry Weingarten

Hi, I don't want to veer into politics, but here is a statement from California's governor, spelling out how the plan is to be largely off of fossil fuels by 2045. https://www.gov.ca.gov/2022/11/16/california-releases-worlds-first-plan-to-achieve-net-zero-carbon-pollution/
Back to the topic at hand, I too have had problems with Rheem heat pump water heaters doing what they want rather than what I ask. I'm thinking they're moody.

Yours, Larry

Mark Eatherton

I find this topic interesting end enlightening, and like all conversations, you have to look at the big picture to see what's going on. I think Ethical Paul is assuming that every home these are placed in are old, with uninsulated basement walls and wide open expanses that are not being used for anything other than spider storage. It is implied that these HP water heaters are running on "FREE" energy, when in reality they are not. Someone paid to heat the air in the basement, especially in homes with finished basements. The rH control is a secondary sales feature that has nothing to do with the heating of DHW.

Full disclosure, I've never worked on one, but my 50 years worth of field experience tells me there a rat out there somewhere. The technicians I've spoken to that are working on them in the field tell me that these units are so incapable of handling the demands, that they spend most of their time running on the heating elements (99% efficient, not 400%) and that the mechanical room is so cold you could hang meat in it, even with a gas or oil fired boiler in the same room, so the consumer leaves the door to the mechanical room open, thereby cooling off the balance of the basement, causing the thermostat to call for heat. Tell me again how efficient these systems are?

Sometimes the Government gets a wild hair up their but and pushes an agenda without really looking at the big picture. Like CFT lighting and the associated UV radiation that is causing major failures of plastic components, including PEX tubing, solar PV with a 20% efficiency and a life expectancy that is less than required to hit an economic breakeven without significant Federal subsidies, and will have to be removed and di$po$ed of with that not being taken into consideration on the initial economics.

The equipment manufactures have no choice but to fall in line, or be over run by the competition. Then marketing gets involved, and pushes silly ideas like "FREE" energy and dehumidification to justify the additional expense. Before you hack my head of and throw it out with the wash, understand that I understand the premise of being as efficient as one can be (COP's of 3 or 4), but I also understand the connected loads (human beings), energy sources (conditioned versus non conditioned space or OSA) and the consumers willingness to stand around and wait for a slow compressor to heat their water to a temperature that they can quickly shower in, all in the name of carbon reduction.

I think one thing that really irritates me in this whole GREEEN SCENEario, is the lack of attention to Solar Thermal (60 to 80% efficient with unknown life expectancies) and NO mention of drain waste heat recovery heat exchangers, which by the way are MANDATORY in new construction in Montreal, and can reduce basic DHW heating energy by 50% (excluding solar thermal contributions) , can be employed now without the need for Federal subsidies.

Why do you think solar PV is so popular with the DOE ? Because it can spin the electrical meter backwards, which is exciting. Solar thermal can't spin the gas meter backwards. It can only stop it and that isn't as sexy as spinning a meter backwards. Bureaucrats are running the DOE. I wonder how many of them own stock in Teslas Power Wall and Solar PV systems... HP water heaters should be drawing their "FREE ENERGY
from outside the conditioned home, but that would require additional materials and labor that will jack the price of an installed system upward, affecting the economics and bottom line ROI, and the Marketing department will fight it all the way to Washington DC

I also think that ALL energy conservation products should have a "Cradle to Grave" environmental listing, that will allow the consumer to look at the options, and make an intelligent economic decision, instead of forcing subsidies down their throat with the attitude of "This is what we have to offer, take it or leave it...". We need to have a bigger voice in what the government is forcing upon us. We are ALL paying for the subsidies, wether we use it or not.

Rant over, open to civil conversations about how to REALLY reduce energy consumption, which I do believe is important, regardless of politics. Waste not, want not.

hot_rod

Any product that is misapplied can, probably will end up badly. Is that the products fault or sale and install ignorance?

there is enough accurate and appropriate information available to get all involved on the correct page. For most any product really.

mod cons have been around almost 30, yet on an almost daily basis we see botched installs here.

Here us a good read for HPWH shoppers, installers and trouble shooters.

 Or troublemakers as my spell check suggested😯

https://idronics.caleffi.com/magazine/33-heat-pump-water-heater-fundamentals

Jamie Hall

Love your rant, @Mark Eatherton ! Now I don't have to...

There is an item I note in the control descriptions of at least some heat pump water heaters: they will switch to resistance mode if they sense the incoming water temperature to be below a certain amount (one quotes 55 F). It is not clear in the description where that is sensed; if it is in tank, it may not be a problem -- or it may, depending on exactly where the sensor is and flow patterns. Why is this significant? Because for many private water supplies in northern climates, the incoming water temperature may be well below 55. Most public water supplies, however, will be at or near that temerature. If this is true -- and I'm not going to say it is, since I've never actually played with one of these beasts, they are remarkably poorly suited to rural communities... like several other wonderful "improvements" lately... oh well.

My contribution to the rant.

hot_rod

I have one, connected it in my shop, sat next to it for a few weeks to observe it run. Measured performance , current draw, decibels of noise, exhale air temperature, 
It does  exactly what the sales and installation manual told me it would.

Yes it makes noise, yes it blows  cold air, yes it took x hours to recover the tank, yes you need to read and understand how the control options 

Not too much to ask in my opinion, read all that online before you buy or sell, or install  one.

LRCCBJ

Mark Eatherton said:

I find this topic interesting end enlightening, and like all conversations, you have to look at the big picture to see what's going on. I think Ethical Paul is assuming that every home these are placed in are old, with uninsulated basement walls and wide open expanses that are not being used for anything other than spider storage. It is implied that these HP water heaters are running on "FREE" energy, when in reality they are not. Someone paid to heat the air in the basement, especially in homes with finished basements. The rH control is a secondary sales feature that has nothing to do with the heating of DHW.

Full disclosure, I've never worked on one,

.

You are correct in your analysis of various scenarios where the HPWH can be placed. I wish to summarize for all what the different scenarios are:

1) Paul's analysis is definitely for a building with an unfinished basement with insulated floor joists. The heatloss via the basement walls (R=<1) is huge. Thankfully, the dirt on the exterior is largely at the same temperature of the basement so we can eliminate that. The heatloss for the foundation wall above ground and below the sill is massive. Typically no insulation and an R value that is worse than single pane glass. Any energy that is produced by the typical losses from a CI boiler in the basement goes right out these foundation walls (above ground level). NOTHING goes from the basement to the first floor. IMHO, this loss is on the order of 12K BTU/hr. It is significant. If a HPWH grabs a portion of this loss and drops the basement temperature slightly, there is no effective cost to the H/O. He is capturing energy that would otherwise go right out of the structure.

2) Your analysis for a building with a finished, properly insulated, and heated basement is correct. The basement loses very little energy to the atmosphere via the foundation walls and the HPWH needs to extract energy from the heated space, thereby reducing the temperature of the space and demanding that the boiler replace that energy. This scenario agrees with your analysis whereby a HPWH is a bit of a scam and will NOT result in anywhere near the energy savings that is promogulated by the manufacturers of said units.

Full disclosure: I've also never worked on one.

Mark Eatherton

Jamie Hall said:

Love your rant, @Mark Eatherton ! Now I don't have to...

There is an item I note in the control descriptions of at least some heat pump water heaters: they will switch to resistance mode if they sense the incoming water temperature to be below a certain amount (one quotes 55 F). It is not clear in the description where that is sensed; if it is in tank, it may not be a problem -- or it may, depending on exactly where the sensor is and flow patterns. Why is this significant? Because for many private water supplies in northern climates, the incoming water temperature may be well below 55. Most public water supplies, however, will be at or near that temerature. If this is true -- and I'm not going to say it is, since I've never actually played with one of these beasts, they are remarkably poorly suited to rural communities... like several other wonderful "improvements" lately... oh well.

My contribution to the rant.

Hi Jamie, long time :-) They reference the incoming water temperature as a departure from normal (low to non load) conditions. A big drop in the incoming water temperature is the ONLY indication of demand, and when it exceeds the capacity of the HP, the backup elements have to kick in at a higher BTUH to attempt to meet the demand. As someone else noted, the factory does NOT like for the Service Department phone number to ring, because usually the 2nd number to get called is Marketing and they absolutely HATE for thier phone to ring from unhappy consumers. I'm working with a company that is getting ready to go into full production on a gas fired ammonia based ASHP, 140% efficient. It sits outside. https://stonemountaintechnologies.com This makes sense. And it does in fact have access to the FREE sensible and latent energy.

Mark Eatherton

hot_rod said:

I have one, connected it in my shop, sat next to it for a few weeks to observe it run. Measured performance , current draw, decibels of noise, exhale air temperature, 
It does  exactly what the sales and installation manual told me it would.

Yes it makes noise, yes it blows  cold air, yes it took x hours to recover the tank, yes you need to read and understand how the control options 

Not too much to ask in my opinion, read all that online before you buy or sell, or install  one.

HR, Managing expectations should be our number 1 job. Like radiant floors in super insulated homes. The floor will never be perceptively warm, except possibly during design conditions. Don't over sell the concept of warm floors. Sell the concept of overall radiant comfort, and oh by the way, you might feel some of the warmth coming from the floors. :-) That and as we tell the technicians in the field, RTFM...

Mark Eatherton

Larry Weingarten said:

Hi, I don't want to veer into politics, but here is a statement from California's governor, spelling out how the plan is to be largely off of fossil fuels by 2045. https://www.gov.ca.gov/2022/11/16/california-releases-worlds-first-plan-to-achieve-net-zero-carbon-pollution/
Back to the topic at hand, I too have had problems with Rheem heat pump water heaters doing what they want rather than what I ask. I'm thinking they're moody.

Yours, Larry

Larry, according to my knowledgeable industry sources, it's a nice goal, but probably can't be met due to grid limitations. They are already doing mandatory load shedding (brown outs). I think gas is here to stay for a while. One of the biggest problems with AI is that it doesn't think like the human that its trying to heat. Look at the Nest thermostat on high mass RFH systems. Too intelligent for the operators, so they overide it and turn it into an expensive IOT device that they can see from outside the home. Can't tell you how many I had to take out to satisfy the consumer who had installed them with grandiose ideas of savings and comfort, neither of which we achieved. Stay well and warm.

SallyM

dean8j said:

. . . Any help would be appreciated, thanks.

Browsing the Rheem website, I found a FAQ for for their hybrid water heaters that states:

Can you put the HPWH into electric only manually?

Yes you can; but only for a short time. The software programming wants the machine to run in an energy
efficient mode. After about 2 weeks in the Electric Element Only mode, the software will attempt to go to Normal mode so it can be more energy efficient. If it does, you will see the mode indicator light on the user control change from Electric Heat only to Normal.

Italics are theirs.

This indicates that the behavior is a design feature; although, like the original poster, we are seeing the mode revert to Energy Saving from Electric in a only a couple days, not weeks.

I have had an issue pending with Rheem technical support since Jan 15 which is still unanswered. I am hoping for a reply. I would like to explain that in the winter, and with our PV system, Electric mode is more efficient than running the heat pump and adding to the heating load of our gas-fired furnace. The heat has to come from somewhere, and their software is effectively turning our new renewable-powered electric water heater back into a gas one.

Until then, I'll keep resetting it every couple days until the weather gets warmer.

SallyM

This is a follow up to my earlier post on Feb 1.

I received this brief reply to my earlier email to Rheem support:

For technical support and assistance with the Rheem EcoNet application or EcoNet WiFi module, please call 800-255-2388 between 7 A.M. to 7 P.M. CST, 7 days a week.

I called this morning and spoke to a technician who was friendly and understanding. He stated that the behavior where the heater goes back to heat-pump mode from electric-only after a couple days is a design feature and that at present there is no way to override. However, he suggested setting up a schedule that is “electric only” for as much of the day as one wants and only in heat pump mode for a minimum of time. That should reset whatever timer the software uses to decide it’s been in electric mode for too long. I will try the suggestion and post back with the result (see below).

He said it will not harm the water heater to be in electric only mode most of the time, it’s just how the current software is designed.

I then asked if he could pass along feedback to the engineering team to consider modifying the software. He said was taking notes and that he would pass back my detailed comments about how, in our case with a PV system and gas-furnace, it is more efficient during cold weather to run electric-only on renewable sources than to capture gas-furnace-generated heat from the household air.

He also said that mine was not the first call about this issue and that if enough people were to register the issue with Rheem, it would be more likely to have an effect. So if you’re also having this issue and so inclined, please call the number above and let them know.

Update 2/12 The workaround suggested by the Rheem technician did not work. The system ran the schedule for two days, dutifully switching to electric mode after a short run of energy-saver each day. But after two days the app displayed a message that the schedule was being overridden and the system had put itself back in energy-saver mode. The app ignored attempts to reset the mode even with the schedule turned off. Only manually setting it back to electric-only on the control panel of the heater was effective.

hot_rod

If the home were heated with an air to air forced air system, then the COP would drop for the HPWH. Here is the math for that calculation. Cascading heat pumps basically.

It would be interesting to run the numbers against a sealed combustion high efficiency gas furnace. The cost of the gas would vary from location to location however.

The efficiency of the home plays a part also.

ethicalpaul

Until then, I'll keep resetting it every couple days until the weather gets warmer.

Why?

veganbeefcake

SALLYM, thank you for the insight! I will be sure to call Rheem and add to the customer complaints.

My heating bill the past two months (Jan & Feb in missouri) were terrible. I decided to investigate and realized my hybrid water heater was pushing way more cool air into our 1,200sqft HEATED basement than originally thought it would. It would be impossible to tell the basement was heated at all. Ok, simple fix right? Just switch to electric👍 two days later it’s blowing cool air into the basement again😑. I’ll try scheduling it in the app and see if that works for me, by some miracle. Explaining this issue seems like people just want to hate on the hybrid water heaters. We like ours and we like the options… when they work

ethicalpaul

I don't hate on them. How is your basement heated? It takes very few BTU to heat DHW compared to heating your house...I don't want to doubt you, but the water heater is cooling off your basement in a noticeable way?