Water Heaters - Tankless water heater

Hello,

I have a standard water heater (A.O. Smith). It is time to replace it and I was thinking of looking at tankless water heaters.

Does anyone have any experience with these?
I found two manufacturers:

1. Rinnai - http://www.rinnai.us/index.asp
2. Bosch (via Home Depot) -
Bosch (http://www.boschusa.com/JumpPages/WaterHeaters/)


Thank you,
Peter.

Before considering any of these units, you need to ask yourself how many fixtures (hot) you will have on at any given time.


This will dictate the size and cost of the unit you are looking at; price means nothing when considering these because if you are draw-comparing from tank to tankless, it won't add up.


GPM flow is your deciding factor, then warranty, then finding out how long that specific has been on the market.

Every once in a while you see someone come into these forums having difficulty finding parts for units they purchased.


I do know that Paul Harvey endorses the Rinnai, but he might not run the dishwasher, the shower and the washing machine at the same time.


If he does, he bought (or was given) a unit that will handle that maximum GPM demand.

I have a Bosch Aquastar 240FX which I installed about 2 years ago. Never had any problems with it and have been very satisfied with it. As mentioned the main thing to know is how many fixtures you plan to run at any one time and then size the unit accordingly. Tankless come in different capacities and I've seen units rated at 250K+ BTU peak which should be able to handle several showers/facets at one time. I'd be careful about getting the 125 series - they may be too small for house with more than one bathroom/shower.

Main points that come to mind

Pros - unlimited hot water supply, cheaper to run (at least for me), takes up less room, no standing hot water in which bacteria can grow.

Cons - Many have to enlarge gas line to 3/4" or 1" depending on model, expensive to install (even for DIY), takes a bit longer to get hot water out, cannot run too many outlets at one time (this is a tradeoff - with a tank you can run maybe 100 facets and be out of hot water in 1 min :D ).

Many people have concerns about repairs/support. I'm not sure how valid that is since I installed the unit myself and also perform the annual service on it myself. However, Bosch is an established German co and Takagi (whih supply the 240FX also known as the TK-1) is an established Japanese co so I would be very suprised if parts are not avialable or become obsolete. I've found controlled energy corporation (who are the dealers in the US for Bosch/Aquastar heaters) very helpful. They have been around for a while and have sent me all the service bulletins/info to service and work on the heater. They will also get you the parts and help you fix it yourself if you have problems.

Hope this info is useful.

Hello,

Thank you for responding.

I have 2.5 bathrooms, plus a kitchen, dishwater, washing machine.

I have called around to some local installers and found a couple that install the Rinnai tankless water heaters. The cost was around $2400. I have not found anyone to install the Bosch (unless I go to the home depot). That is way too expensive compared to traditional water heaters. I do not think I would be able to install this on my own. I know I would have to increase my gas line.

Someone I spoke to also said that these systems will sometimes decrease the water flow so that the "heating" can keep up. Has anyone seen this behavior?


Thank you,
Peter.

Sounds like you need a Takagi TK-2 or equivalent. You can see this model on their web site which is www.takagi.com. I'm not familiar with the Rinnai brand. For something like a TK2 I think you would be paying around $1000 + installation. In my case I bought the 240FX for around $600 and it cost be another $300 or so to install - this included a bunch of tools as well as the metarials like the larger gas lines and venting. $2400 sounds pretty high to me. I'm not sure in genral why tankless cost so much to buy and install. I would have thought the manufacturers would drop the price to promote sales of the tankless units over the tanks but apparently this is not the case

Someone I spoke to also said that these systems will sometimes decrease the water flow so that the "heating" can keep up. Has anyone seen this behavior?

Yes, this is sort of true. For the model I have there is a flow rate limiter which limits the max flow to 5.3GPM. This will vary with the model but is there as you said to ensure the water does not run completly cold. Given that you will be mixing hot and cold water normally this flow should allow 3-4 fixtures at a time.

Their tech told both me and my plumber that the Bosch is expected to fail every 2-3 years. I now have a $950 wall decoration.

Very surprised by this. Can this info be backed up by statistics. Bosch is a very well known German brand and have a reputation for quality. I have a hard time believing that they can gurantee only a 2-3 life on their products?? Things like hard water may cause them to fail earlier but things like this are excluded under warrantly and the installer should be aware and install means to flush/descale the heater if needed.

Their tech told both me and my plumber that the Bosch is expected to fail every 2-3 years. I now have a $950 wall decoration.



That is not good but I am not suprised. Buildup in those even though you try to descale them will always buildup. I have taken out insinkerator hot water dispensors with brass canisters that broke apart at the soldered seam due to the buildup inside of them.

By no means am I an expert on these whatsoever. If they sold the canisters on all these tankless for $50, (which they probably never will) the benefit would be worth it.....but I think people like the "put it in and forget it plumbing" in their homes.

Very surprised by this. Can this info be backed up by statistics. Bosch is a very well known German brand and have a reputation for quality. I have a hard time believing that they can gurantee only a 2-3 life on their products?? Things like hard water may cause them to fail earlier but things like this are excluded under warrantly and the installer should be aware and install means to flush/descale the heater if needed.
I paid $950 and the warranty was only 2 years on parts. The distributer told me and my plumber that the 125FX (Electric ignition) told me AND my plumber that as a rule they fail every 2-3 years. I wouldn't have the statistics but obviously they do.

And my well water is very soft. My Koi love it.

That is not good but I am not suprised. Buildup in those even though you try to descale them will always buildup. I have taken out insinkerator hot water dispensors with brass canisters that broke apart at the soldered seam due to the buildup inside of them.

By no means am I an expert on these whatsoever. If they sold the canisters on all these tankless for $50, (which they probably never will) the benefit would be worth it.....but I think people like the "put it in and forget it plumbing" in their homes.


Dunbar: What is this canister you mentioned for $50? Can you provide a picture of it? What does it do?

The very small compartment where the water is heated. Like I stated though that part will never be replaceable I'm sure. You will probably have to buy the whole unit over again. I am not sure since I rarely install these units, along with hardly ever troubleshooting since they are not as common as tanked heaters. I have seen though in some circumstances that they are beneficial, but keep in mind they do not cover all basis for all situations.


The good thing is that like 1.6 toilets when they came out they were perfected over the years to make a really good one. Same will follow for the tankless unit.

Very surprised by this. Can this info be backed up by statistics. Bosch is a very well known German brand and have a reputation for quality. I have a hard time believing that they can gurantee only a 2-3 life on their products?? Things like hard water may cause them to fail earlier but things like this are excluded under warrantly and the installer should be aware and install means to flush/descale the heater if needed.
My kit is not exact but it is showing a PH of 7.0 or higher (soft).

Very surprised by this. Can this info be backed up by statistics. Bosch is a very well known German brand and have a reputation for quality. I have a hard time believing that they can gurantee only a 2-3 life on their products?? Things like hard water may cause them to fail earlier but things like this are excluded under warrantly and the installer should be aware and install means to flush/descale the heater if needed.
He said the ignition system will fail roughly ever 2-3 years no matter what your water is like. Ask my plumber. He heard it too.

Sorry to hear about your problems. Have you complained to Bosch about your situation. Maybe they may cover the repairs under warranty if they feel that you are a dissatisfied customer. To me it sounds like you have been unlucky - manufacturing is not perfect and sometimes people have things that fail just outside of the warranty period leaving them feeling like the products stinks as you put it.

I still have a hard time believing the story about the ignition. It may well be true or it may simply be a poor attenpt by the tech to justify what happened. In any case he should have tried to help you out instead of giving you such comments which can only serve to worsen the situation.

I simply gave the example of the hard water to show that some things may not be covered under warranty. I agree this has no bearing in this case.

Unfortunately with the Bosch line of products the warranty only covers the parts - not labor. So unless you are comfortable working with water heaters (as I am) it can be bit difficult to find people to install and fix these things.

The very small compartment where the water is heated. Like I stated though that part will never be replaceable I'm sure. You will probably have to buy the whole unit over again. I am not sure since I rarely install these units, along with hardly ever troubleshooting since they are not as common as tanked heaters. I have seen though in some circumstances that they are beneficial, but keep in mind they do not cover all basis for all situations.

I think you are referring to the heat exchanger. In most of these heaters this particular part has a very long warranty period (I think 15 years). Tankless water heaters seem somewhat of a new concept in the US but has been in widespread use in places like Japan and continental Europe for years. Many home have a tankless and hot water boiler combined into a single unit (combination or "combi" boilers). I have seen tankless heaters over 20 years old over there still working on the original parts even those that are in hard water areas. The one thing I do recommend is that a tankless be serviced every year according to the manufacturer's service schedule.