Tankless with well water??

Discussion in 'Tankless Water Heater Forum' started by M3, Jul 9, 2009.

  1. M3

    M3 New Member

    Messages:
    39
    Location:
    Minnesota
    Without reading every thread out there, I haven't seen anyone questionusing a tankless with a well supply.

    We remodeled two bathrooms with a 40 gal tub and a 60 gal tub and have a multi head body-shower. The problem is that we still have a 40 gal tank heater... I knew it couldn't keep up with hot water and would have to get a larger unit, but am wondering if a tankless would be a good fit.

    The well water sits around 50 degrees F and I'm wondering which would be best...
    A: installing a good tankless
    B: using the current 40 gal tank heater as a staging tank (not heating) and installing a good 75 gal tank heater as the main
    C: installing just a new 75 gal tank heater
    D: using the current 40 gal heater as a staging tank (not heating) and installing a tankless as the main.

    E: Other ideas??

    I do have the room for two tanks but it would be a bother, and we plan on staying in the house for several years. My wife likes "hot" baths and showers and I don't want to be replacing this after 5 years.

    Thanks in advance for your insights.
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,013
    Location:
    New England
    What is your water hardness? What fuel do you have available? Electric would require a very significant supply. So would gas. On a bigger tub, it's nice to have large flow volume so you don't wait forever to fill it. This means you must put a huge amount of energy into the water to get it hot enough as it flows by the heat exchanger (think hand through a candle - a blowtorch will get you hotter when passing by at the same rate). To get the flow for multiple showerheads and other things that may be using hot, you may need multiple units.

    The varying pressure could present a problem as the temperature might either rise as the pressure drops (decreased flow), or it would be constantly adusting the burner, if it deals with that that way. There are ways to keep the pressure fairly constant with a well.
  3. M3

    M3 New Member

    Messages:
    39
    Location:
    Minnesota
    Thanks for the thoughts JD... water hardness is not too bad (as tested by a water softener company last year). I have natural gas and most of the supply lines going to the bathrooms are 3/4".
  4. 75 gallon gas

    water heaters seem to last forever on wells, wether their
    is a lot of iron and hardness or not...


    you cant claim that with a tankless
    the water softener is required with the tankless..

    do you have a water softener

    also, I am not sure how well a taknkless works when the well has a pressure drop in it as the pump kicks on??
  5. SewerRatz

    SewerRatz Illinois Licensed Plumber

    Messages:
    1,705
    Location:
    Chicago, IL
    I have seen a few tankless installs on wells, as long as there is a water softener, there would not be much of an issue. You will have to descale it on a regular basis. Properly sizing the tankless system will be more an issue for you. To be able to handle your multi head shower while others may be using hot water as well I would install a pair of Noritz N-0751M-DVC units. The DVC is a concentric direct vent unit, it also links easily with each other via one plug and play cord. Only real issue is making sure you have enough gas supply to both units and the rest of the gas appliances in the home. Many installs go horribly wrong when people assume their gas meter is properly sized. So its best to talk to your gas company about your meter size even if you decide to go with a single tankless unit.

    So other than proper gas sizing and the cost to install two units it would give you endless hot water for years to come as long as you descale them on a yearly schedule.
  6. Dana

    Dana In the trades

    Messages:
    2,841
    Location:
    01609
    Do you have a hydronic (forced hot water) heating system?

    If yes, the better option is likely to be an indirect-fired tank running off the boiler. Done right, that will usually be both a cheaper & higher-efficiency way to get the hot water (improving the as-used AFUE of the boiler), with none of the flow & cold-water sandwich issues associated with a tankless. If the boiler's output is on the low side for an indirect, you can up-size the volume of the indirect to meet your tub-filling capacity needs.

    An indirect-fired tank will generally outlast the boiler, with lifetimes similar to or exceeding a tankless, and much lower maintenance to boot. And an indirect's standby losses are miniscule compared to a standalone tank. When the heating system is hydronic, indirect-fired hot water is almost ALWAYS the better/cheaper/more-efficient way to go. Summertime efficiency won't generally be as good as a tankless, but it can be close (depends on the mass and combustion efficiency of your boiler.)
  7. Scott D. Plumber

    Scott D. Plumber In the Trades

    Messages:
    67
    The Answer is "A"

    Get a good tankless. Go with a Rinnai R 75 LS series for up to about 3 "Normal" bathrooms. If you have more than that consider a "twin R75 installation as an option. Have it installed professionally by a qualified, licensed and insured contractor and you'll be very happy.

    The Rinnai is a high quality unit and has a 12yr warranty on the main part and 5 years on everything else.
  8. SewerRatz

    SewerRatz Illinois Licensed Plumber

    Messages:
    1,705
    Location:
    Chicago, IL
    Have you looked into Noritz at all. They have the same warranty, but personally after taking the required classes for both I feel the Noritz is a much better unit over all. One of the things that really impresses me with the Noritz is the dual flame burner which helps add the burning of any unused gas and really stabilizes the temperature. Also the controllers that come with the Noritz can do all the advance settings where the Rinnai comes with a basic controller if you wanted to raise the output temperature you would need to purchase their advance controller. Here is a link comparing the R75LS to the N-0751M-DVC http://www.noritz.com/u/noritz_751m_vs_rinnai_75ls.pdf

    One other thing you said the R75LS can do 3 normal showers, that is with 65º - 75º incoming water temperature. With the 50º incoming temperature the original poster stated he will be able to run 2 normal showers with no issues but once the third is ran he will notice a pressure drop.

    Noritz does make a unit called the N-0931 that will do the 3 showers with 45º incoming water temperatures. But personally I would rather install a pair of N-751 units for just a few bucks more in cost (N-931 retails for $2,099 the N-751 retails for $1,299). This way with the 50º incoming water temperature you would be capable of getting 9.6 GPM (Duel R75LS would give 8.6 GPM). As well you would have redundancy with a second unit, meaning down the road when one needs repair the other one will still be providing hot water till you get the repairs done.
  9. Dana

    Dana In the trades

    Messages:
    2,841
    Location:
    01609
    It's possible to roughly double the heating capacity for shower flows by raising the incoming water temps several 10s of degrees with a ~$600-800 drain-pipe heat exchanger (eg. GFX, Power-Pipe). While this does NOTHING for tub filling (it's a counterflow heat exchanger, the drain & incoming water must flow simultaneously to get the benefit), if it saves the cost of a second tankless to serve the shower it can be worth it in up front costs alone. (It'll save 30-70 therms of NG/year too depending on your well water temp, the plumbing setup & your use patterns.) See:

    The performance measured

    Where to get 'em:

    http://www.conservationmart.com/p-714-power-pipe-drain-water-heat-recovery.aspx

    http://www.gfxtechnology.com/GFX-LC.sales.htm

    http://www.efi.org/wholesale/pdfs/power_pipe.pdf

    A handful of US states/utilities offer energy-efficiency subsidies for them too (but for some, only if the primary HW heat is electric.)

    The colder the incoming water, the greater the benefit, but if your well water was 65F+ already, you'd be able get by with a single tankless anyway.
  10. gusherb94

    gusherb94 Member

    Messages:
    124
    Location:
    chicago/nw IN
    I would do the simplest and lowest maintenance in the long run thing, which would be simply upgrade to a 75 gallon tank.
  11. yours is the best answer so far....

    gusher, you are very wise... the simple path is best..
    and its the path that will keep his wife happy too....
    .

    but alas, its not as hot and flashey and trendy like a tankless.

    so no one wants to listen ....






    your answer is best but
    you really need a better avatar..
    the pink toilet aint hacking it....:D:D.
    Last edited: Aug 20, 2009
  12. gusherb94

    gusherb94 Member

    Messages:
    124
    Location:
    chicago/nw IN
    I don't think tankless is even worth the extra price in most cases, like in our house we use quite a bit of hot water. The 100 gallon whirlpool get's filled halfway everyday and about 2 shower's are taken everyday one being a long shower (yes me I'm the long showerer:D), the dishwasher gets run every few days and the washer almost everyday often many times a day using hot or warm water.
    The hot water source being the 19 year old Ruud high recovery 50 gallon water heater.
    In the summer when only the clothes dryer and water heater are being used the gas usage is always 15-20 therms and the bill about 40$

    I'm meaning to change that avatar but can't think of any photo's I have plumbing related that are "cool".
  13. macmikey

    macmikey Macintosh Computer Consultant/Tech

    Messages:
    4
    Location:
    Phoenixville, PA
    I have the Rennai R94LSi and I am very happy with it. My kid (a girl) and her mom like to take long hot showers and her Mom likes to take a hot bath at night, usually while the girl is in the shower for school the next day.

    Not once since we switched to the Rennai have we experienced low pressure or warm water instead of hot. I even ran the dishwasher and a load of clothes one day while both were showering (yeah, I know a little cruel if it did not work) and neither said the water slowed down nor the temperature get cooler.

    We have it on LP gas, Well pump at around 60PSI, 3/4" mains throughout and 1/2" drops. The unit is extremely quiet (my daughters room is about 10 feet away) and it just performs flawlessly. I am considering a remote so we can dial in the Hot water temp for a shower (only if one using it though) and not using cold water to see if that is even better.

    Mike
  14. Scott D. Plumber

    Scott D. Plumber In the Trades

    Messages:
    67
    Yep

    Actually, Yes I have. I used to use them and switched to Rinnai for several reasons. The link you post is one of them. It kind of irritated me that they would tell “untruths†about the competitor to sell their stuff. I’m ok with leaving things out. (All of them will do that) but to actually make stuff up is not cool. Dual burner or not, they both give you within 2* setpoint and the Rinnai remote keeps you from going over 140* because you will get hurt! You don't ever need over 140* in a house. It's not safe. Even 140* is way too hot.

    They like to compare the 931 to the R75 don't they. They won't talk about the R94 will they. Guess why?

    For instance…â€Rinnai’s concentric vent line uses less durable galvanized steel or plastic and requires cutting to adjust the vent lengths.†Not true. Rinnai is a heavy Aluminum inner and PVC outer concentric…JUST LIKE THE STUFF THEIR COPY CAT UNIT NOW USES. They came out with that one because Rinnai was kicking their tail with a vent that was easier to run. “You can cut it†is one way to say “You have to cut itâ€.

    They also don’t want you to know that unless you pay more money for a DV unit, your water heater is a “Power vent†not “Direct vent" and has further clearances to windows or doors and is subject to sucking up whatever is in the space where it lives. (Like cat hair) Never a problem with Rinnai because ALL of their models are DV and all but one is single pipe concentric.

    For instance #2: Commercail Grade/Standard Grade. Not true. The LS series is all commercial grade and Noritz is no thicker. That’s why Rinnai went to a 12 yr warranty. They don’t want you to know that.

    #3: Full Diagnostic mode: That one is total BS and they know it. Ever Rinnai comes with a remote just like theirs except for a (1) builder grade low output model. All remotese have full diagnostics just like theirs. They also fail to tell you that you can have up to 4 remotes on a system with Rinnai and you can’t with Noritz. Which means if you want one at the unit, at the master tub and at the Kitchen sink…you can’t have it. If you installed the Noritz in the crawlspace you cannot have a remote at the heater for service and another at the bath or inside the house. Rinnai also has a remote that will up your master tub and shut off the water when it’s full! It even talks to you. They don’t want you to know that either. They also don’t want you to know that ONLY Rinnai has a Lime scale error code to warn you of a scale up condition BEFORE the unit goes out on a high temp warning which makes successful flushing of the unit a lot more likely…especially with well water.

    #4 Simple High Elevation Adjustment. Let’s see, flip one dipswitch or unplug one clip. Not a big difference there is it? They want you to think it is.

    #5 Built in pump control. They don’t want you to know that it only runs a 80 watt pump. Too small to be of use with their tankless water heater. They also recommend as does Rinnai the use of a De’mand system by ACT metlund or your warranty goes to 3 years (Both Lines) Noritz changed their warranty a couple years ago from 10/3/0 to 12/5/1 to match Rinnai because they were losing that battle.

    While I’m at it, their BTU and Flow rate comparison is choosing a higher output Noritz against a lower Output Rinnai. Hardly honest don’t you think? They don’t happen to mention that with Rinnai you get 24/7/365 tech support…an Engineer in GA and they only have 8am eastern-8pm Pacific Mon-Fri, if you can get through.

    Now all that said, Noritz makes a great product. If I could not get a Rinnai, I would go back to them. I just wish they were a bit more honest and had better tech support and better training. Is you do a Rinnai ASP class, you’d really see a difference. When you make a good product you don't need to make up stuff to sell it. THat kind of thing looses respect from me.

    Don't worry though. As long as I'm around none of these guys are going to get away with anything.

    So what really made me switch in the first place? The local Noritz rep does not know a tankless water heater from a hair dryer and with these things you better have a good local rep to help you when you need it. If your Noritz rep is great, I’ll bet that’s why you are so happy with them. Once I switched I learned the rest of the story. Now Noritz has a few advantages too, however since they withheld info and stacked the deck…I think I’ll keep them to myself... for now.:D

    Don’t forget both models require a drain pan if the unit is to be installed in an area where a leak could cause damage! (See their installation instructions) If ou put in enough for long enough, you’ll find out what happens when they reach the end of their lifecycle. Look up “The Wall Saverâ€
  15. nofears67

    nofears67 New Member

    Messages:
    186
    I am in almost the same boat wondering whether to go tank or tankless on a new home my wife and I are building. I was originally going with a 55 gallon Bradford White high recovery GX-1-55S6BN tank unit. I also am on a well that puts out water in the 55* range, with a hardness of 320. We run propane. I will have a large tub and a couple showers with multiple heads/body sprays.

    Now I'm thinking of using two Rinnai tankless heaters in series, both the 9.8 models since the mstr bath has the potential to demand about 20 gpm at one time.

    3 bdrm
    2.5 bath (9 - 2.5 gpm heads in one, 2 - 2.5 gpm heads in another)
    1 - 100 gal soaking tub

    One 50 gal tank will serve the laundry, kitchen, pwdr bath, and 3 utility sinks. The master bath and the 2nd bath are the ones I'm unsure how to serve.

    Oh yeah, we'll be using a water softener as well.

    Any advice would be appreciated.
    Last edited by a moderator: Jan 9, 2010
  16. propane tankless ???

    being on propane makes me think you are out in the boonies
    somewhere....

    keep that in mind when you need service someday..

    the two riannias are as good as any of them....
    if you are hell bent to go propane tankless.




  17. nofears67

    nofears67 New Member

    Messages:
    186
    Well not really in the "boonies", but off the beaten path enough that the Gas Co. has not brought lines up here, just like there are no public water lines here either...fine by me as well water is MUCH CHEAPER!

    There are plenty of certified plumbers in the area so I'm not worried about future servicing of a tank or tankless heaters. As a matter of fact my mother in law, who lives just up the road, had a tankless installed about a year ago.

    One of the reasons we're thinking about tankless is that currently the BW 55 gal heater, that we have configured, is in a small closet inside our master bedroom walk in closet. This closet will be accessed from the outside but it is taking up valuable space in our closet that would otherwise be an additional 6 linear feet of shelf and pole (two 3' sides of a square).

    A tankless could be installed on the outside of the home thus we would regain the space in our master WIC.

    We just want to make sure we build this the right way when it comes to hot water demands. It is very common for my wife and I to take showers at the same time in the evenings after working on the ranch all day. If we were to do this the potential total water demand could be in the range of 30 gpm from the two showers if all heads were running (not likely, but possible). I realize that not all 30 gpm demand will be "hot" water.

    We are at an elevation of 4332 and we get very cold temperatures, freezing at times and occasional snows. Not sure how outdoor tankless solve this situation.

    I really appreciate any and all advice and information. THanks!
  18. nhmaster

    nhmaster Master Plumber

    Messages:
    3,189
    Location:
    S. Maine
    My rule of thumb is

    never put a tankless heater in a friends house
    never put a tankless heater in a relatives house
    never put a tankless heater in your own house

    :D:D:D
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