Tankless issues

[Preston1977]

At the end of August I replaced the old tank water heater with a tankless Rheem RTG-84 XLP-1 and it’s been very disappointing. My house is a 2 bath home, both bathrooms are about 35’ away from the water heater. No matter the temperature outside the water heater is very inconsistent with providing hot water. The hot side of the valve can only be slightly on to provide hot water to either tub, if I crank the valve wide open the pressure drops drastically and the water gets room temperature at best. The 2 showers, kitchen sink and bathroom sinks get just above room temperature but keep pressure.

Has anyone experienced this and if so how’d you resolve it? I’ve had 2 plumbers out and neither can figure out. I’ve reset it with no luck and checked the filter. Calling customer service gets me no where. I’ve seen a YouTube video where the home was comparable to mine and plumber installed 2 tankless water heaters in tandem with no problems. Thanks in advance, Preston

 

[havasu]

Have you read the reviews for this unit? Not too favorable. I would either return and replace this unit, or add a recirculating system.

 

[Preston1977]

Unfortunately i didn't read them until day 2 after the install 😐🔫. I tried a recirculating pump but the water heater constantly threw a fault code. I kinda have been leaning towards replacing it with a different brand and I was prepared for that answer lol, it’s such a turd

 

[havasu]

I had a Navien TWH installed, and it comes with a recirc pump built into it, along with a hot water chamber to stop the hot/cold/hot system. I loved it until I sold that house.

 

[CT-18]

you need to know temp rise at what flow rate. If your water comes in the house at 65 and you want 120 out that is your rise. So you need to find the flow rate at 55-degree rise. It is throttling down because it can only heat so much water at such a flow rate.

I wish people would educate themselves because some of these companies only want to make the sale. Then it is to bad for you.

 

[Socal37plumber]

You might want to check,the gas line feeding your water heater.I come across many tankless heaters.And they are installed,without the installer doing the correct gas calculations.
Btw way Rheem in general isn't the best manufacturer out there.Norowitz is the tankless I install.

 

[Preston1977]

you need to know temp rise at what flow rate. If your water comes in the house at 65 and you want 120 out that is your rise. So you need to find the flow rate at 55-degree rise. It is throttling down because it can only heat so much water at such a flow rate.

I wish people would educate themselves because some of these companies only want to make the sale. Then it is to bad for you.

Yeah I certainly didn’t do enough homework before I made the purchase. I was solely focusing on gpm. I didn’t know there was a more to it than that nor did the plumber I work along side of give me that much guidance.

 

[Preston1977]

You might want to check,the gas line feeding your water heater.I come across many tankless heaters.And they are installed,without the installer doing the correct gas calculations.
Btw way Rheem in general isn't the best manufacturer out there.Norowitz is the tankless I install.

The gas company down here came by prior and did the calculations and told me what I needed to do to get the btu’s. I had to put the house on a 2lbs system with 2 separate lines beyond the meter each with its own regulator. 1 line feeds the house while the 2nd is solely for the water heater. The line to the water heater is 1”, 27’ in total length, only 1 90 and reduces down 4” from the the water heater.

 

[Preston1977]

I’m currently looking at a Rinnai RU98EN. I can pick it up for around $1300 shipped, twice the cost of that rheem but if it works then it’s worth it. I just have to do some research on the temperature rise. I’m about 10 miles SE of New Orleans so we only get this freezing weather for a week or 2 out the year so the water temperature out the ground usually isn’t freezing cold.

 

[JHEARD]

This doesnt speak badly for rheem. I agree with CT-18. Had the temp rise been taken into consideration you could have selected the correct Rheem heater. There are other factors that can affect your sittuation. I work on tankless heaters every week. The problem a vast majority of the time isnt with the product. The problem originates in installer error. weather that be by neglecting gas flow and temp rise or just not installing properly weather it be gas supply, venting, or pipe run length. there are many possible reasons why a unit wont work properly when not all factors are taken to consideration.

Rheem Tankless heaters are extremely easy to service and the parts are all simple to install. wire hookups are such that you cant plug anything in wrong. You can however shoot yourself in the foot from the start if you are unaware of what the heater you chose is capable of or how it needs to be installed.

Did anyone ever hook a manometer up to the gas inlet on the heater and test for water column?

I'm a little late on seeing this but my associates and I are always looking for more info and scenarios to help us out in the future.

 

[RenewDave]

Yeah, JHEARD is correct. You need to “hire” a professional tankless service person. First question before hiring, “do you know what a manometer is?” Second question, “do you own and know how to use one?”. Even an undersized unit should produce hot water. You need a service person to diagnose the exact reason the unit isn’t getting to temp. When I service a tankless I bring in 2 tool boxes and a iPad. I wouldn’t eat the first unit until I knew why it wasn’t performing correctly. A trained plumber should tell you what is going on and either fix it or give you a plan on how to fix it.

 

[JHEARD]

Yeah, JHEARD is correct. You need to “hire” a professional tankless service person. First question before hiring, “do you know what a manometer is?” Second question, “do you own and know how to use one?”. Even an undersized unit should produce hot water. You need a service person to diagnose the exact reason the unit isn’t getting to temp. When I service a tankless I bring in 2 tool boxes and a iPad. I wouldn’t eat the first unit until I knew why it wasn’t performing correctly. A trained plumber should tell you what is going on and either fix it or give you a plan on how to fix it.

also a good idea with tankless to bring a multimeter. if you have a troubleshooting guide for the heater you are working on it will have all the resistances and voltages of the wires and what they control. checking these readings can be time consuming and probably why a lot of plumbers skip this step and just replace the heater. but with tankless its not like tank heaters, not hard to repair. if you can find a plumber who is willing to do the digging there is a good chance you can save yourself a lot of money. replace one wiring harness instead of an entire water heater.

i know rheem's troubleshooting guide is easy to follow and covers just about every possible problem for every error code there is. including a diagram for if/then and what the reading should be and how to remove and replace every part in the unit. if anyone wants a trouble shooting guide i can include a link to the online copy. VERY HANDY

 

[breplum]

It goes without saying, that your installer should be taking complete responsibility for this. You should not be incurring added costs.
The unit should be under warranty of minimum, 5 yr parts and 1 year full labor.
The factory warranty ought to supply you with a service person if your installer doesn't respond.
Go to the Rheem website to see if that is an option.
For the only brand we install, Navien, they are called NSS (Navien Service Specialist). They are required by the company to respond to service requests that are under warranty, and to do it on the reimbursement level that the corporation pays.
Where you can get screwed is, if the installation is at fault, you will be on the hook.

 

[frodo]

It goes without saying, that your installer should be taking complete responsibility for this. You should not be incurring added costs.
The unit should be under warranty of minimum, 5 yr parts and 1 year full labor.
The factory warranty ought to supply you with a service person if your installer doesn't respond.
Go to the Rheem website to see if that is an option.
For the only brand we install, Navien, they are called NSS (Navien Service Specialist). They are required by the company to respond to service requests that are under warranty, and to do it on the reimbursement level that the corporation pays.

Where have you been?
vacation?

Where you can get screwed is, if the installation is at fault, you will be on the hook.

 

[breplum]

Frodo, not vacation, just mostly on the Plumbing Zone site for professionals only.
In semi/mostly-retirement, I only have limited patience for DIY questions.

 

[RenewDave]

Patience? You’re required to have patience? I missed that.

 

[frodo]

you were missed

 

[OldernDirt]

Yeah, JHEARD is correct. You need to “hire” a professional tankless service person. First question before hiring, “do you know what a manometer is?” Second question, “do you own and know how to use one?”. Even an undersized unit should produce hot water. You need a service person to diagnose the exact reason the unit isn’t getting to temp. When I service a tankless I bring in 2 tool boxes and a iPad. I wouldn’t eat the first unit until I knew why it wasn’t performing correctly. A trained plumber should tell you what is going on and either fix it or give you a plan on how to fix it.[/QUOTE

Hmmm, "Manometer?" This sounds like something the wife has that keeps track of my "Honey Do" list she gives me! Do I know how to use one? NO, but I can tell you one thing for sure she is an "Expert" in it's use!

 

[MoNs00n]

I have found Navien to be the most reliable tankless heater.
It not only features a integrated recirculating pump model but also in many cases be installed with the remaining gas supply.

A few items I would check first would ofcourse be if the dip switches are set correctly, if the flow rate sensor reading correctly and clear of any foriegn debris, what the output temperature is set at.
If the gas pressure is less than adequate the unit would throw a error code and shut down.
Truly sounds like a flow rate or dip switch setting issue to me without being onsite and info gathered from my seat here at home sipping coffee and watching the sun rise on this beautiful Sunday morning.

Calling tech support would be the game changer in this case.
They would walk you through all these checkpoints.

 

[MoNs00n]

One more note of importance is that the original installer should have never left you home without correcting this MAJOR problem.