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Thread: Experience with tankless LP water heater

  1. #31
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    Quote Originally Posted by Jim Becker View Post
    One other suggestion for these newer systems that have electronics (tankless heaters for sure, but other items, too, including mini-splits, etc.)...put a surge suppressor on the power outlet for the unit. A new "brain" can cost nearly 2/3 of the cost of a new water heater. Twenty bucks now is totally worth it. I did have a unit get fried, but fortunately, it was near to the expected end-of-life for the system anyway.
    Jim, which surge suppressor do you use? Just regular surge protector, like 3-6 outlet extender, or surge suppressor installed in panel?

    Thank you, Ed

  2. #32
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    I nstalled a Rheem gas model. I like it. A drawback is that it takes a few seconds longer for hot water to reach fixtures. Once there though you never run out. I think due to their complexity they are more prone to repair/ replacement. Yearly maintenance recommended also for descaling. At least with my gas model.
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  3. #33
    Quote Originally Posted by Jim Becker View Post
    One other suggestion for these newer systems that have electronics (tankless heaters for sure, but other items, too, including mini-splits, etc.)...put a surge suppressor on the power outlet for the unit. A new "brain" can cost nearly 2/3 of the cost of a new water heater. Twenty bucks now is totally worth it. I did have a unit get fried, but fortunately, it was near to the expected end-of-life for the system anyway.
    In my opinion, the manufacturers should put surge suppression into their equipment. It's not that expensive, especially for something expensive - like a tankless water heater - it wouldn't affect the end price very much. My guess is that they do put some level of surge suppression in the units but probably not sufficient to withstand a lighting strike.

    Mike
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  4. #34
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    Quote Originally Posted by Eduard Nemirovsky View Post
    Jim, which surge suppressor do you use? Just regular surge protector, like 3-6 outlet extender, or surge suppressor installed in panel?
    Just a single, plug-in unit. It probably wouldn't stop a "direct hit", but it should help with. I don't have whole house suppression, unfortunately.

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  5. #35
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    How much maintenance do tankless heaters need in locations where there are a lot of minerals in the water?

    What's the peak AMP draw of the electric versions? That could be a problem in older homes with only 100 AMP service.

  6. #36
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    Quote Originally Posted by Stephen Tashiro View Post
    How much maintenance do tankless heaters need in locations where there are a lot of minerals in the water?

    What's the peak AMP draw of the electric versions? That could be a problem in older homes with only 100 AMP service.
    About once a year for the back-flush scale maintenance, Stephen.

    For Electric units (which I wouldn't recommend for general use for energy cost reasons and sometimes smaller capacities than gas; but they are great for spot needs or vacation cabins, barns, etc.) the amperage requirements are going to vary with size/flow rate. Electric units can be provisioned to service a single room, such as a bathroom, laundry or kitchen, which can lower the amperage requirement for a single unit and make them more acceptable for service in dwellings that have older/smaller panels.
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  7. #37
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    Quote Originally Posted by Stephen Tashiro View Post
    How much maintenance do tankless heaters need in locations where there are a lot of minerals in the water?
    They cannot tolerate scale build up, so if you have very hard water, either you have to soften the water to a low mineral burden before heating it, or you'll be descaling the water heater multiple times per year. In order to heat the water quickly, these machines run it through heat exchangers with fairly narrow channels and lots of surface area, so scale builds up quickly, and will damage the water heater by stopping flow fairly easily, if not controlled.

    Quote Originally Posted by Stephen Tashiro View Post
    How much maintenance do tankless heaters need in locations where there are a lot of minerals in the water?

    What's the peak AMP draw of the electric versions? That could be a problem in older homes with only 100 AMP service.
    You can get them at nearly any size, but if you want to heat water for a shower or any other high flow applications, you need at least a 100 Amp unit (and it will draw 100 Amps). 100A at 240 volts is 24Kw, which is roughly 90K BTU/hr, which is marginal. Even my mid-size LP gas model is rated at 120,000 BTUs, and while the electric ones are somewhat more efficient at converting input energy to heat, it's not by much.

  8. #38
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    Quote Originally Posted by Steve Demuth View Post
    They cannot tolerate scale build up, so if you have very hard water, either you have to soften the water to a low mineral burden before heating it, or you'll be descaling the water heater multiple times per year. In order to heat the water quickly, these machines run it through heat exchangers with fairly narrow channels and lots of surface area, so scale builds up quickly, and will damage the water heater by stopping flow fairly easily, if not controlled.



    You can get them at nearly any size, but if you want to heat water for a shower or any other high flow applications, you need at least a 100 Amp unit (and it will draw 100 Amps). 100A at 240 volts is 24Kw, which is roughly 90K BTU/hr, which is marginal. Even my mid-size LP gas model is rated at 120,000 BTUs, and while the electric ones are somewhat more efficient at converting input energy to heat, it's not by much.
    This is true. A proper install includes clean out valves where you can hook up a back-flush system. What I do is use a submersible pump in a Home Depot bucket full of white vinegar. I back-flush it with that for 20 minutes or so about three times per year. It isn’t hard, but it is a downside to tankless heaters if you are taking score.

  9. #39
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    We have had a Rinnai for several years and itd provides superior service to the gas water heater it replaced.
    I take long showers and never run out of hot water. It also handles the washing machine quite well.
    The only gas appliance we have is the central heat and ac.

  10. #40
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    Dec 2019
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    Quote Originally Posted by lowell holmes View Post
    We have had a Rinnai for several years and itd provides superior service to the gas water heater it replaced.
    I take long showers and never run out of hot water. It also handles the washing machine quite well.
    The only gas appliance we have is the central heat and ac.
    So this is electric, or?

  11. #41
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    Aug 2011
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    Thumbs up

    Funny, a "power event" (likely a surge) screwed up the circuit board in my previous boiler so I ended up switching it and the tank-style water heater to a Navien tankless LP combi-boiler last year. Been great so far, love the utility room space I gained back from the other two units as well.


  12. #42
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    Feb 2003
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    Peter

    That's a really nice install on the plumbing, Those are nice sweated joints!!! The gas looks a little different to me.
    if you did it yourself, well done. If you had it done, definitely keep that person's card!
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  13. #43
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    Dec 2017
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    WNC
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    I installed 3 navien ng ones and they work as expected, yearly cleaning routine is easy to do.
    One is in my house and is a bit overkill because I am alone but the one at my buddies house with 3 heavy additional users replaced a regular one which was often overwhelmed by the demand and they love it.
    One thing really easy to get used to is the hot water circulating loop on my unit.

  14. #44
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    Quote Originally Posted by Mike Cutler View Post
    Peter

    That's a really nice install on the plumbing, Those are nice sweated joints!!! The gas looks a little different to me.
    if you did it yourself, well done. If you had it done, definitely keep that person's card!
    Thanks, the guy that did it is a "hobbiest plumber" that works for the propane company here. Took two days and included some other re-work of the system, he did an awesome job of it.

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