Tankless-luke warm shower

Discussion in 'Tankless Water Heater Forum' started by wt, Jan 30, 2009.

  1. Redwood

    Redwood Master Plumber

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    That is Correct!
    It is time Laddy it is time...
    Answer the questions...
    Your credibility is shot!

    The debating practice of deflecting any question given without answering it,
    and then throwing a question to the opponent may work in a presidental debate but it ain't workin here!

    Answers Laddy Boy Answers!
     
    Last edited: Feb 10, 2009
  2. Redwood

    Redwood Master Plumber

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    Look back to posts #127-129 in this thread.
    They await your reply!
     
  3. sjsmithjr

    sjsmithjr In the Trades

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    Legionella

    Thanks for taking the time to clarifying your position re the occurrence of Legionella, Ladiesman. That does indeed make me feel special! Per your request, here is my understanding regarding the topic.

    It is important to recognize that any water distribution system where the temperature ranges between 70 to 120F is a potential source for Legionella regardless of the type of water heater used. In warmer climates, it is not uncommon for the temperature of the cold water distribution system to be within the growth range. Piping materials used, the proximity of the distribution piping to heat sources, dead ends, etc are also variables to be considered.

    Even at temperatures in excess of 130F, Legionella can survive 5 to 6 hours. Instantaneous kill is not achieved until 160F.

    In the Canadian study sited earlier, the temperature in the bottom of the electric water heaters where Legionella was observed was typically between 85F and 105F. No reason was given for maintaining the temperature that low or if the heaters in question where single element. The recommendation was to raise the bottom temp in those heaters 140F.

    I should note that in the preceding I have rounded the temperatures given for ease of discussion and that the actual temperatures would be slightly different.

    Of course, the preceding discussion completely ignores the effect of chlorine on different types of bacteria, including Legionella. Many variables come into play, such as pH, temperature, residence time, and the amount of chlorine present. I could address that as well if anyone is truly interested.

    The point of all of this is that the use of a tankless system does not preclude the presence or growth of Legionella. Your statement that "no water storage in a tankless means no water is stored at the optimum temperature needed to create a breeding ground for bacteria either" is false. I hope I have helped both you and other readers of this forum understand some of the reasons why.

    That's all the leisure I've got for today!
     
    Last edited: Feb 10, 2009
  4. SewerRatz

    SewerRatz Illinois Licensed Plumber

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    Excellent reply there sjsmithjr, what you said there was one of the things I learned in one of the many plumbing classes I had to take. Thank you for taking your time to explain it for everyone here on the forums. It is the false assumptions people make that can get lots of other people ill, or even kill them.
     
  5. Ladiesman271

    Ladiesman271 Homeowner

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    Since you knew those facts from all those plumbing classes you had to take, can one presume that you installed a whole house tempering valve in every water heater that you ever installed or replaced? Just wondering if you followed though with your knowledge.


    Note that with no tempering valve installed it is not legal to have hot water in the tank above 130 degrees F (per MA code anyhow)!
     
  6. Ladiesman271

    Ladiesman271 Homeowner

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    OK, I see that you prefer to use legal verbiage. I did not think that I had to run an internet posting by a lawyer before I posted here.

    The little water that is stored in a tankless water heater is stored at room temperature, so it is not any safer nor more dangerous than cold water that is stored in the cold water pipes. You flush out most of the "stagnant" water from the tankless hot water system end to end by the time you get hot water to the point of use. The complete flush of the hot water system is performed many times each day.

    That is hardly the case with a tank type water heater. A complete flush of a water heater tank is rarely done at all. Bacteria loves to colonize in those tanks when the water temperature is set "too low". With no tempering valve installed at the tank, the legal high temperature limit is considered to be "too low" for what we are discussing!
     
  7. SewerRatz

    SewerRatz Illinois Licensed Plumber

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    One thing I pride myself on is doing things to code. Yes If the homeowner had concerns about bacteria growing in their tank I did install a whole house tempering valve and set the heater to 140 degrees. I also made sure they where able to run all the fixtures in their home as the same time. As well as set the tub and shower limit stops to 115 degrees per the code. One other thing I install is an expansion tank, and if the water heater is on the first or second floor I also install a vacuum relief valve per the plumbing code. And guess what I am a licensed plumber so I am not violating my states laws about practicing plumbing with out a license. How about you, are you a licensed plumber or did you have one install your water heater?
     
  8. SewerRatz

    SewerRatz Illinois Licensed Plumber

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    They love to colonize in the heat exchangers as well. If you truly think a tankless heater is not at risk, you are sadly mistaking.
     
  9. Ladiesman271

    Ladiesman271 Homeowner

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    Yikes, you are depending on the homeowner to know all about about what you learned in your plumbing class? :eek:


    While we are talking about "the code", at least you are on the my side of an old discussion when it comes to air gaps being installed in a dishwasher drain line. It is not required by the MA plumbing code, so you would never install one if you were a plumber in MA unless the homeowner asked for one to be installed.:D
     
  10. Ladiesman271

    Ladiesman271 Homeowner

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    You and the "boys" better take some action against a ton of plumbers / dealers /distributors for making false statements in that regard if you truly think that your statement is accurate!


    One of many examples:
    [​IMG]
     
    Last edited by a moderator: Apr 8, 2020 at 9:55 PM
  11. sjsmithjr

    sjsmithjr In the Trades

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    Thanks for adding that. You would still have to heat the water to 140F to purge the lines of Legionella bacteria. I believe (as in I don't have time to check myself right now) the prescribed remedy for pasteurizing infected systems is to heat the water to 160F for 24 hours and flush each outlet for 20 minutes.

    Bottom line: if you are concerned eliminating Legionella you have to heat the water, regardless of method, to 140F and reduce the temperature at the point of use to the temperature specified by the code followed in your area. Cold water lines must be kept below 65F.

    If I'm mistaken, someone please let me know, but please don't go quoting a sales brochure.
     
  12. nhmaster

    nhmaster Master Plumber

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    SJSmithJR, Nice post and thank you. I need to calarify a couple things for our more literate readers though. Legionella bacteria will propogate at the right temperatures in any piping. The tank is really no more of a breeding ground than the supply and distribution piping is. Legionella bacterial is highly resistant to chlorene and only chlorene in doses high enough to kill humans will kill legionella bacteria. Of course even in moderatly high concentrations chlorene becomes highly caustic so chlorination is not a viable option. Water temperatures higher than 160 degrees have been found to be effective at killing the majority of the bacteria but it has been found that the bacterial can and will re-propogate further down the distribution lines. Therefore the best recommendation would be to set the thank to 160 and install tempering valves at each fixture as close to the outlet as possible. Installing a tempering valve on the tank, while somewhat helpfull, will not necessaraly kill all the bacteria as there can still be colonies growing in those pipes that are seldom used. Here's where we begin to run into problems with tankless heaters as they can not be operated at temperatures that high. Code review boards have been kicking legislation addressing this problem around for a few years now and have not yet made a decision most likely because of the money involved and pressure from various interested lobbiests. The stark truth here is and always has been that any plumbing inspector could very well prohibit the majority of tankless installs based solely on their inability to provide continuous hot water at a continuous temperature to every single fixture in the home at the same time. That is the reason why tankless coils in oil fired boilers have all but dissapeared from the scene.

    I hereby certify the entire post above to be completely and totally Google Free and of my own creation
     
    Last edited: Feb 10, 2009
  13. Ladiesman271

    Ladiesman271 Homeowner

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    You still have problems downstream even if you boost the temperature in the hot water tank if you have a recirculating system installed. The recirculated water needs to be at that same higher temperature. That means more complications of having hot water that is over the 110 degree limit at the fixtures.

    One good thing is that if you have copper pipes, then that helps out with the issue of bacteria (of all types).
     
  14. Ladiesman271

    Ladiesman271 Homeowner

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    You now have added a few more words to the hot water requirements. Now in order to fail this test you have established the requirement to have the "inability to provide continuous hot water at a continuous temperature to every single fixture in the home at the same time".


    So now we have to finish things up. What is the minimum hot water temperature and the time period of the hot water draw that will permit one to pass this test? The minimum pressure values have already been established.


    Even with a tank type heater if all the hot water fixtures are operated at the same time the hot water will not last very long. Furthermore, is the test for all fixtures turned on simultaneously (both hot and cold)?
     
  15. Scuba_Dave

    Scuba_Dave Extreme DIY Homeowner

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    So HOW exactly do you supply 2 showers running at the same time??
    Actually how do you use ANY 2 devices at the same time?

    still waiting
     
  16. SewerRatz

    SewerRatz Illinois Licensed Plumber

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    At least a tank heater can supply water at mutiple fixtures at one time. A tankless system can do this as well but you need more than one unit. Which I been saying for some time now.
     
  17. nhmaster

    nhmaster Master Plumber

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    I teach 52 high school students each day, 13 plumbing I & II apprentices two nights a week. Teach plumbers re-certification classes 4 to 6 times a month and run another 6 to 10 seminars a year on subjects ranging from backflow prevention to solar water heating. Untill this fella and his cohort came on the scene I have never in all that time, even dealing with drooling freshmen, had any one as frustratingly ignorant as this guy. I think in my zeal I may just have overlooked one very saliant premiss here though. I think these guys just plain like to argue for the fun of it. I was gonna put them both on the ignore list but truth is sometimes it's kinda fun seeing just how brick headed and wrong a fella can be.
     
  18. SewerRatz

    SewerRatz Illinois Licensed Plumber

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    I never put anyone on ignore, I like to see what they have to say no matter how brickheaded they are.
     
  19. Master Plumber Mark

    Master Plumber Mark Sensitivity trainer and plumber of mens souls

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    no matter how sutpid they are.....


    its sort of like slowing down and looking at a traffic accident...

    or like
    shock and awe at someones stupidity, I suppose..
     
  20. sjsmithjr

    sjsmithjr In the Trades

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    QED; I'm done with this one.
     
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