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Thread: Tankless Water Heater

  1. #1
    DIY Junior Member shall's Avatar
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    Question Tankless Water Heater

    I have just purchased a NORITZ tankless water heater.

    The unit is installed on the inside side of the exterior wall near the garage door entrance. The Gas meter is about 5 feet away from there and has a T connector on top where the 3/4 and 1 1/2 line to the rest of the house is connected. There is a 1/2 line off the main 1 1/2 feed going across the house in the ceiling that was run down the inside wall to feed the old water heater..

    To use the existing 1/2 line for the tankless the length would be about 12-15 feet of 1/2 pipe. Big resistance to gas delivery I think. I want to use the T off the top of the meter and run a 3/4 inch supply to the NORITZ to satisfy gas delivery requirements and run would be 5-6 feet total of 3/4.

    Is it ok to use the T connector from the meter by removing the plug? Looks like an easy run and wil be a total of about 5 feet from source to the water heater.
    Last edited by shall; 04-02-2007 at 01:53 PM.

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    Retired Defense Industry Engineer jadnashua's Avatar
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    First, what do the specs say on the heater installation manual? My guess is maybe the 3/4" may be too small. Do not try to use less than they specify. If that is okay, I think pulling the plug and using that outlet should be okay, but wait for one of the pros to comment. Depending on the model selected, some of those tankless systems can require significant supplies. With a significant supply comes the need for air and exhaust, but having it outside helps. Wouldn't work where I live - too cold, but okay for some.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  3. #3
    DIY Junior Member shall's Avatar
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    Quote Originally Posted by jadnashua
    First, what do the specs say on the heater installation manual? My guess is maybe the 3/4" may be too small. Do not try to use less than they specify. If that is okay, I think pulling the plug and using that outlet should be okay, but wait for one of the pros to comment. Depending on the model selected, some of those tankless systems can require significant supplies. With a significant supply comes the need for air and exhaust, but having it outside helps. Wouldn't work where I live - too cold, but okay for some.
    Specs show that gas volume is 25k min to 199k max. So I thought that I would have a range but the length of 1/2 pipe looks like it delivers less than half the 3/4 line. Was not sure about the availability of the T with unused port. All painted grey so not sure to whom it belongs. Me or the gas company? Or does it matter?

  4. #4
    Retired Defense Industry Engineer jadnashua's Avatar
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    Normally, everything past the gas meter is yours. Local rules may be different. My guess is that that heater is spec'ed at at least a 3/4" supply line, and maybe 1". If you want it to work right, follow their instructions. Most inspectors will require it to be installed per the manufacturer's instructions.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

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    DIY Junior Member shall's Avatar
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    Default Tankless Water Heater

    Thank you for the response to my dilema. I did go ahead and made the 3/4 line hook up. The spec didn't really say that it had to be 3/4 but could not meet the gas volume spec maximum with out it. Maybe the minimum would have been ok but don't know how that would affect the performance. All this since this is my first and only tankless installation.

    If I had it to do over would leave the storage tank in place. Hope it is all worth the effort.

    Stan

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    Master Plumber master plumber mark's Avatar
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    Talking tankless exaust heat question......

    never undersize the gas to one of those units.
    it will cause you nothing but troubles....

    Which Nortiz model did you buy???

    I have a brand new one that does about 6.9 gal per minute
    and am thinking about doing an experiment with it...


    I am curious as to how well it will work...

    and I am very curious about how hot the exaust vent gets

    on the outside of the home??

    Is your stainless steel exaust line going out the side of your
    house at about knee height ???

    I have been told it can get as hot as 300 degrees so you certainly

    dont want your kids to touch that if this is true..


    if you dont mind the risk,
    would you please do a little
    experiment and see how hot that diverter Tee gets
    whe the unit if fired up and cooking...>>>>

    I probably would not lay my hand on it

    but maybe crack an egg on it when its heating and
    see if it actually cooks it....

    or try some sort of thermometer

    thanks
    Last edited by master plumber mark; 04-05-2007 at 02:51 PM.

  7. #7
    DIY Member gmrules's Avatar
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    I have a LP Nortiz, I have been using it for almost 3yrs no with no issues

    The thing that bugs me is when u lose power you have to press the power on button on the remote to get h.w again. If you do not know u lost power over night Cold shopwer in the morning till u realize to check the remote. Mine was in crawl quickly moved indoors after I found this out.

    Mine is Outside and has done its job well 3 showers at once no issues not sure if I have the 6.9 or 8.4 sorry

    The cool thing is if one units not enough u can run then in series off one remote


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    DIY Junior Member viennamicro's Avatar
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    Default Tankless Comment

    I installed my Bosch unit with double walled exhaust lines and a booster fan. The outer walls of the vent lines are only warm to the touch. The area to be concerned about in my case is the outside vent cap. I'm vented out the basement wall to an area of the flowerbed with no plants (intentional). The vent can be more than a little warm - too warm for me to try to touch.

  9. #9
    DIY Junior Member shall's Avatar
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    Red face Tankless Water Heater

    The Noritz that we installed is the 069-M for medium to heavy residential use. Since there is usually only two of us it seemed that the 6.9 gal average with a 45 degree temp rise that this should work for us. So far it has done ok but I am a little discouraged about hte length of time it takes to bring hot water to the faucet/sink. Seems to take a little more time to reach operating temp than storage type heater. However once the hot water is at temp it stays there. There is a little flucuation when opening the second or third faucet or shower. Seems to maintain flow ok though. Not too much different than storage tank but don't run out of hot with multiple activities going on.

    The exhaust is hot but not red hot. The wall feed through thimble is well made and protects combustible wall material. I didn't have a thermometer to check it with but is hot-hot. I have the unit mounted about head high to the center and the exhaust is above that so won't burn any one unless they purposely touch it.

    The control unit is mounted on the wall beside the heater and is very easy to see and operate.

    I am retired from a communications (telephone) background so am not a plumber. This project just sort of grew out of redoing a bathroom and I was curious about the "Tankless Heater" option. So got in a little over my head. But it does work.

    I am not even close to being a plumber. So here I am, Stan

  10. #10
    Retired Defense Industry Engineer jadnashua's Avatar
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    Well, my incoming water in the winter is about 33-degrees, so add 45 - humm, 78-degree showers...sounds like fun. Hopefully, you are in an area where your supply water never gets very cold.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  11. #11
    Master Plumber master plumber mark's Avatar
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    Talking nortiz 69-m

    That is the unit I have new in the box....

    supposed to do about 7 gallons per minute...

    I had heard that it was extremely hot at the exaust...

    and Ihave been told two different stories about how hot that
    stainless steel single walll pipe was going out of the house got to.....

    one sales person told me that the TAKAGI SS single wall
    pipe did not get hot to the touch, which sounded like a total load of hooey..

    so now I am wondering if you had to run this across
    your basement through a joyst how hot that SS exaust pipe
    gets before it reaches the end of the run...???

    I wonder if that pipe in your house can be touched,
    and wether that is considerd a fire hazard going through the home
    any distance at all with something above scalding hot??






    still pondering wether to instal this puppy or not...
    Last edited by master plumber mark; 04-10-2007 at 10:54 AM.

  12. #12

    Default

    10 to 15 feet of 1/2 inch iron pipe, should be well within the capacity for LP.

  13. #13
    Master Plumber master plumber mark's Avatar
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    PEW.......Should is the majic word here........


    Like.....I should have invested in Microsoft back in 1983.....
    Now I would be worth something


    I should lose some weight......
    then i would not be so overweight...



    most problems with those units according to the TAKAGI man is
    undersizeing the gas inlet....


    good luck

  14. #14
    Master Plumber Dunbar Plumbing's Avatar
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    Default I almost pulled a Don Imus yesterday

    Customer called, had a 100 year old home that it was advised by a home inspector that the gas water heater was venting into the basement instead of the chimney, and that he recommended putting, get this, a small ceramic space heater in a pipe leading into that chimney to keep it warm so the furnace AND the water heater an ability to properly draw up the chimney.

    Now if that isn't a nappy-headed ho, I have no idea what the **** that guy was thinking giving that woman that kind of advice, knowing CO is entering the basement.....and pushing a sale of a home on through.

    She's a single woman, her heart is set on a PowerVent heater to abandon the chimney all together. I could of mentioned a flue liner but that would involve changing her mind.

    She did however mention tankless, I went over the numerous conditions she would have to prepare for in regards to its installation. Her usage of water was ideal for a tankless but I lost her when I told her that she would have to size the tankless to accommodate a 70+ degree rise for the cold climate in this area. Plus, twice the cost to install, plus, no one around to service the unit.

    I told her that she'd have to clean the unit per say mfg. instructions either quarterly or yearly to maintain the efficiency of the unit.

    I told her though that she was the first one in a long time that had the possibility to get one but the cost would double over the PowerVent......and she'd have to get a maintenance agreement with *someone* who is well versed on the product.

    She's going to get a PowerVent installed and correct the problem with the chimney for under $1500.00 installed, materials included. I don't think a tankless would fit that mold, especially considering the temperature rise. It was 18 degrees a couple nights ago. Ground didn't freeze because it was too warm weeks prior but believe me, it made a few water heaters go POP because of the longer heating cycles.


    I can see where tankless would be a hit in warmer climates. In arizona I hear the incoming water is like 80 degrees? That's less than 30 degree rise and that would be nothing for a tankless to generate and maintain a high GPM flow rate on numerous demands.
    Last edited by Dunbar Plumbing; 04-11-2007 at 08:43 AM.
    Read what the end of this sentence means.

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