Navien Tankless Water Heater Comments and questions

Discussion in 'Tankless Water Heater Forum' started by willl, Dec 28, 2008.

  1. SewerRatz

    SewerRatz Illinois Licensed Plumber

    Messages:
    1,706
    Location:
    Chicago, IL
    Most guys end up changing brands due to their supply house changing brands. My supply house went from Takagi and Noritz to Navain since Navain has a better price margin for them, I started buying my tankless units at a different supply house now. Granted I have to travel an extra 20 miles to pick up a unit that I know and trust that works, but it is well worth it knowing the peace of mind my customer and myself will have.
  2. Dovels INC.

    Dovels INC. New Member

    Messages:
    7
    wow good reply and i agree with you totaly. zl700 name should be zero because the manuals are only as good as the engineers that write them and i must say that the navien manual is week maybee they should put shop service manuals in the box so us non educated plumbers cand help re engineer naviens junk that we hang on the wall
  3. zl700

    zl700 DIY Senior Member

    Messages:
    237
    Location:
    Texas
    Ok suggestion received

    If I ever write a manual, I will write 2, the second one for a second grade education.
  4. sammy5619

    sammy5619 New Member

    Messages:
    1
    Location:
    charlotte
    Navien

    I looked at all tankless models and the bottom line is this. Until an independent neutral party tests all units then you can't believe anything! It's just like politicians saying this and that. When you go to fact checker most of what they say is skewed. Noritz, Rinnai, Takagi, and Navien reps and salesmen are on here with one goal and that is to confuse and create doubt, and make their unit sound like the best.. Here is the 1 constant I have seen in tankless heaters. 90% of the issues are the result of improper heater sizing, improper gas line sizing (I met a plumber who didn't know what a manometer was) or improper installation. All units have training classes for installers so I would suggest going that route. I have put in all heaters and have had general issues with all of them. As for Navien I just started with these and did have to do a software upgrade on some units and older units I had I switched out the boards before I sold them because I heard they had issues with the first release. Anyway I guess I am a little more forgiving as I was defending Noritz and Takagi when they came out. Does anyone remember all of the issues we had with those? Anyway until someone like Consumer Reports or an independent testing facility tests ALL UNITS I take everything with a grain of salt.
  5. its all just smoke and mirrors

    Its all smoke and mirrors...

    that is the best approach with these tankless units..... it all should be taken with a grain of salt....

    prople ahve been indoctrinated into thinking
    this it the holy grail....and they must have one

    I could not even convince a customer over the phone that they are probably going to burn their house down..... because they tied in their bosch unit into the existing flue off the furnace..

    I dont know where my moral responsibility ends
    here....

    you can tell them ,
    but they just dont waant to hear you

    let it burn down, I guess.... .








  6. heetmiser

    heetmiser New Member

    Messages:
    2
    Location:
    NY
    Well, after about a month of noritz installations I am happy to report, no callbacks, no start-up problems and no BS to deal with. Is noritz more money? yep, and worth every penny.
    Sorry for the delayed responce to who asked what we were installing, it was rinnai, but started with navien because of the high eff. and the ease and flexiblity of pvc venting. noritz offers all this with MUCH better presure drops thru the heat exchanger, and just a better quality unit.
  7. Dovels INC.

    Dovels INC. New Member

    Messages:
    7
    i have installed the noritz also only 3 but i agree ///// by by navien //// my main problem is the cost if you put a pensil to it the cost of a tankless will never add up my gas bill is 46 to 56 a month with a 20 dollar meter charge so my gas usage cost me 26 to 36 a month. So the tankless will probably save me 5 to 10 a month providing there is no repairs its still a 15 to 20 year payback
  8. zl700

    zl700 DIY Senior Member

    Messages:
    237
    Location:
    Texas
    I think the average savings in a normal household tankless gas over tank is about $120 per year. While many are confused or misled about tankless savings, many buy tankless for other reasons.

    It like the logic of buying a hybrid vehicle. You save gas, but the added cost of vehicle, life expectancy, higher service costs in some cases, along with the impending battery replacement and disposal costs, negate all that.

    People still buy and drive them though, and like tankless wont go away and only grow in use and popularity.
  9. Dana

    Dana In the trades

    Messages:
    2,802
    Location:
    01609
    I don't think I've met ANYONE who went residential-tankless strictly for the fuel savings. The most common reason I get is that they have some monster tub or spa to fill and they didn't need/want/have-space-for a 100 gallon tank to handle the tub-filling load.

    For others it's just about saving space.

    I've seen commercial food-prep installations where fuel savings was a primary driver though.

    For me it was a cheaper/more efficient option than a cast-iron boiler. They're dynamically scalable to the anticipated load at the design phase, and using a reverse-indirect as a HW heater/buffer, can be designed to modulate much of the season on combined DHW + heat loads, at a fraction of the cost of a mod-con + indirect. The difference in fuel use between a mod-con + indirect vs. using a tankless for the radiation I have in place would be on the order of 50-100 therms/year, not more. Installing a drainwater heat recovery at the same time recovers a similar amount of heat for a fraction of the delta in price between a mod-con & tankless, and reduces the peak load from showering by ~25-35kbtu/h, and allows one to set the modulation point closer to the heat load, while still delivering pretty-much endless hot water in showering mode. (I don't have a spa to fill.)

    With the indirect acting as buffer and keeping boiler loop flow under 2gpm it may even outlast a tankless used strictly for DHW, since it'll cycle an order of magnitude fewer times, and never short-cycle. (Lifetime TBD, but if it doesn't go more than 10 years, no BFD. But if it craps out in 5, I may do something else.)

    When somebody comes out with a condensing boiler that modulates between 15-50KBTU/h for under a grand (or the subsidies for condensing units goes even through the roof) I'll think about it. In the meantime you can buy a stack of bottom-of-the-line Takagis for the current price of a 50-60KBTU mod-con. They don't have to last forever to be cost-effective.

    Of course I coulda just went with a tank HW heater & heat exchanger combi with a 60K burner and saved something up front, but if the tankless gives me 10 years I've made back the difference on performance, even at a buck-a-therm-delivered. I'll know in a few years if I made the right gamble, but even if I lose, I won't have lost much.

    Previously I'd lived 15+ years with a less efficient atmospheric-drafted tankless serving DHW loads only, which was perfect for our serial-showering/bathing needs- we never ran out. It's output was low enough that mid-winter laundry needed to be scheduled around bathing, but it wasn't a major inconvenience. I'm sure it paid for itself in fuel savings at least 1x over, but for us it was more about 3-4x serial showers/bathing than it was ever about fuel savings.

    Clearly YMMD.

    BTW: Battery replacement & maintenance issues on hybrid cars is much overstated- they tend to last WELL beyond the warranty period, and the batteries have significant scrap value- (there IS no disposal cost to the car owner.) The majority of Prius owners never replace the NiMh battery, many are retired after 200K miles with the original battery still working. Extreme cold weather areas have higher failure rates. Used-yet-functional Prius batteries can be had for under a grand on the secondary market, so if you're well past the warranty on your high-mileage vehicle you don't really HAVE to sink anything like the $3K dealer price of a brand new battery into a rolling wreck past it's prime. (Newer Li-ion technology is likely to have even lower failure rates though.) The life-cycle costs are still lower for a hybrid in an NPV financial analysis, (to be sure it DOES take awhile), but the added costs of hybrids do not in fact "...negate all that...", in the majority of cases so far.
  10. Runs with bison

    Runs with bison Member

    Messages:
    892
    Location:
    Midwest
    Storage heating is only costing me about $40/year based on a test I ran on my system. Since recovery efficiency is not all that different from tankless there is not much additional there for me except for condensing operation. The venting/air supply changes required would be substantial though in my home.

    Most of those are common misconceptions, at least if one is talking about the most common hybrid:
    1. The added cost is pretty slim anymore if you are comparing to the same size/capacity options, and will be recouped if resold--the premium is still there.
    2. Life expectancy is really not substantially different since components can be replaced, just as with other vehicles.
    3. Service cost can actually be lower because of fewer brake jobs (regenerative braking means the original brakes tend to last extraordinarily long times.)
    4. Hybrid component warranties (yes, including the battery) are 8 years, 100,000 miles in most areas, 10 years, 150,000 miles for CA and some other states. So if the pack goes prematurely, you are covered. The new battery pack lists for about $2,500 now if it fails out of warranty (and they can be found at a markdown from some Toyota parts dealers.) Compare this with the chances of an automatic transmission failure in the 100,000+ or 150,000+ mile range and make a guess as to which is a better financial bet.
    5. There is no disposal cost of the battery. The nickel inside is valuable and Toyota offers $200 for the old ones.
  11. cassquervo

    cassquervo New Member

    Messages:
    1
    Location:
    cali
    I can not speak for those that live in the cold, but those that live in warmer climates, I say look into the unit that serves you best. Before I began installing them for customers, I installed one on my home and put it through the paces for a year. I installed a Noritz. Pros: Instant 30 - 40% drop on my gas bill with no notice of electrical increase, great longer showers and no waiting for the water to reheat due to previous use, indoor programmable thermostat with easy to follow error and info codes.
    Cons: Annual service is best to maintain unit ( but it is simple to do yourself ), cold water sandwich, location can make installation costly, most installers don't let you know or include in their installation the service valves.
    The unit I installed is now considered old. There are now even more efficient units and some of the older units have come down in price. The new Navien units are nice and solve part of the problems with internal buffering tanks to prevent "cold water sandwich" and a built in circ pump to eliminate additional installation charges. The down side is that some of the plastic parts fail soon after installation. Navien will quickly send out a replacement and pay the Navien tech to replace it. That part is not so bad. The only true negative I have for the unit is the noise made by the operation of the gas valve solenoid valve. This wont be a problem if the unit is not installed on a wall to a normally occupied room like a bed rom or family room.
  12. AAnderson

    AAnderson In the Trades

    Messages:
    36
    Location:
    Aptos, CA
    tankless

    In 36 years of working on tankless, I've seen them go from a campfire in a box to truly amazing marvels. In the last 10 years, it was Rinnai that put tankless on the map. Bosch limped along through CEC until Bosch bought and bit the hand that fed them. As I tell customers, if you love French cars, you'll love owning a Bosch because they are the most counter intuitive tankless o the market. Navien hit the market and as posted, running a sack race with Bosch in last place for tech support. I haven't had any problems with Navien but they are noisier than the others apart from what they claim. I had the city of San Jose, CA reject Navien's exterior Moose head venting configuration and was not pleased with support (severe lack of) regarding that project.. Rinnai's technical support has been consistently superior in every respect but like all technical support, it's only as valuable as the information giving. the tech isn't on scene and many times there are conditions you are not aware off; example a new installation in Morgan Hill, CA had an error code 12 after a few months of operation. The manometer showed 7" W.C and quickly dropped to below 3". I stated it again after 5 minutes and the same thing occured. My first thought, they have a quake safety valve and sure enough, one was at the meter close to the street, do the math. Problems aren't always in the box, most are outside of it.
    Because you can hold a tool and have an opposable thumb doesn't mean either you are capable of working on tankless, it takes years and other skills like micro electronics, single and dual digital manometer, combustion gas analyzers, a variety of digital multi meters in your tool inventory and the background and experience to use them correctly is the difference between a happy customer and a bad rap for the industry.
    If sized and applied correctly, tankless is clearly the better choice. If we are the last society addicted to tank culture, bigger is better, than plumbers not on board with tankless are going to be extinct in a few years.
  13. Runs with bison

    Runs with bison Member

    Messages:
    892
    Location:
    Midwest
    The chances of tanks being extinct in a few years are nil. There are two primary reasons: 1. Massive installed tank user base, small tankless user base. Retrofits are an expensive PITA in many cases, so they are not going to happen. 2. The energy cost of storage is not nearly as great as suggested by the tankless folks.

    Then there are other secondary reasons. Condensing storage over the next few years will bridge the efficiency gap for all but the condensing tankless. And they can acheive a high burn rate without the usability pitfalls of the tankless. There is a lot of room to maneuver for condensing storage designs.

    Passive solar is another problem for the idea that storage will disappear. There will be a storage tank with passive solar. And if I was targeting energy efficiency in the South, I would start with passive solar, leapfrogging any fuel consumption tankless could accomplish. What it is paired to for supplemental heating is a smaller concern.
  14. AAnderson

    AAnderson In the Trades

    Messages:
    36
    Location:
    Aptos, CA
    In 1976 few if any households had a computer, give tankless the same time frame. I started installing Paloma in the 70's along with Aqua Star before Bosch bought them. The industry has come a long ways since then.
    At my primary wholesaler, Ferguson, tankless far out sell tanks. No other country in the world uses tank technology to the degree we do in the US.
    As tankless becomes more widely accepted, tanks will go away like the 7 gpf wall mounted toilet tank of the 1920's, cast iron residential waste and threaded galvanized steel water pipe. All replaced with material easier to install and handle. They all had there time. It;s taken the unions in my area 10 years to accept PEX and some are still fighting it. They fought copper and ABS for decades.
  15. zl700

    zl700 DIY Senior Member

    Messages:
    237
    Location:
    Texas
    Tankless outsell tanks?
    That would be the only FEI branch in the world where that happens

    Actually according to gas residential shipment reports tankless sales are about 12% of all gas residential water heaters in the US

    This year a dip in sales is being experienced but also with tanks with an industry that is down almost 35% compared to 2008.
  16. MechGuy

    MechGuy Plumber @ Mechanical Contractor

    Messages:
    9
    Location:
    Iliinois
    Balderdash

    Gosh it's nice to know people who know everything. Plumbers love tanks because, especially in emergencies, no one questions your charges or cost or efficiency they just want it fixed. You draw down the old heater, snap 2 water connections off/on, 1 single wall or "B" vent exhaust and the cash is in your pocket.
    You can make a ton of money a week just doing tanks but in my area the tankers are known as the N*****s of the plumbing fraternity.
    Insulation didn't beef up in tanks until the FVIR system came along with it. Wholesalers bought literally a million extra tanks the year before FVIR came in just to avoid it as long as possible.
    NH you're familiar with tankless if you're using the Buderus GB142 with a Priority circuit for DHW so don't shame tankless.
    Show me a tank capable of producing 250 gals per hour?
    And you Combi criers.....radiant despite it's real efficiency and comfort will always be backseat to FA till people give up CA/C. Paying for Ducts and tubes isn't rational in a less than luxury house.
    And as to Market penetration it comes with Marketing. Tankless had it so easy coming ashore in CA they have no idea how to market to the rest of America. I deal daily with Noritz, Takagi, Rinnai, Navien, Eternal, Rheem/ECO, Bosch and most of their RSM's and Mfrs Reps are clueless.
    I reinstall 100's of units a year installed by DIYers, handyman and, yes, fellow licensed Master Journeyman Plumbers who miss or screw up important installation requirements.
    New rules or ideas have never been welcomed into plumbing; FVIR omg no, indoor plumbing, Mr Rudd's Water Heater,
    When you started installing tanks there were no 7 head human car washes flowing 17.5-22 GPM. New Technology.......I was installing tankless Burkay coil units in 1979 in conjunction with 300 gal storage to produce huge gph.
    Cold water sandwiches can be overcome by about 3-4 methods every plumber should know or have been taught (I know them and there ain't no big red "S" on my chest).
    In Japan in new building the water heater is universally piped and actually moves with the homeowner from residence to residence as they buy/sell their units. Except for the initial piping, plumbers are cut out of the loop there after in dealing with moving or replacement of water heater.
    Jist is get familiar with the future. Feedback improvements to Mfrs and maybe, just maybe you'll stay in Plumbing or Fittings and not lose your way preaching the old tyme religion.:eek:
    Yesterday ain't tomorrow and it sure as heck ain't next week.
  17. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,888
    Location:
    New England
    Many of the indirects can produce that and more. Mine is rated at over 266 gallons, it's actually more since the boiler fires up a bit hotter than the 180 and less than the higher value. And, it does it at mid-90% efficiency all day long, which a tankless won't do. I do have a nice wall-hung Buderus unit. Can fill my 6' air tub while doing dishes, washing clothes at the same time without worring about flow issues or running out of hot water.
    http://www.htproducts.com/literature/lp-81.pdf
  18. Dana

    Dana In the trades

    Messages:
    2,802
    Location:
    01609
    An indirect is only as "big" from a first-hour rating point of view as it's volume and the boiler behind it. In MANY instances you'd have to oversize the boiler for the heating load in order to deliver anything like 250gallons/hr.

    My indirect is rated for 907 first-hour 140F gallons, but it takes a 500KBTU/H burner to deliver that. It'll deliver 267 first hour gallons with a 200K burner behind it, but my design day heat load is under 30K, and a 200K burner would make absolutely NO sense, even a 100K burner is 3x oversized, and would only deliver ~150 first-hours gallons.

    But using a tankless as a boiler, and the indirect as a buffer, the tankless will modulate to match the load for the DHW, and it's average output under heating loads is less than 1.5x oversized, with decent minimum-burn times to keep the efficiency from falling off a cliff. I won't be filling a 100 gallon spa with 115F water with this system in the dead of winter, but with the extra kick from drainwater heat recovery I can run showers continuously, even under more-severe-than-design-day heat loads and never run cold.
  19. MechGuy

    MechGuy Plumber @ Mechanical Contractor

    Messages:
    9
    Location:
    Iliinois
    You forgot

    Basically unless you designed it from the start any shower waste water would have to be lifted to flow through your Waste Water Heater Recovery System.
    This adds a cost you're ignoring. Also a BTU return loss in your recovery calculation.
    These system are most efficient when gravity designed.
    Manly men plumbers hate them as they constantly whine that graywater will eventually contaminate freshwater in these systems while these systems are U/L and UPC listed.
    Just as out friend nashua is so opposed to tankless 50+ year ago he would have raged against copper vs. galvanized pipe.
    Tankless isn't perfect but improved and lowered in cost and designed in from the beginning it will eventually replace tanks.
    Ever visited a flooded basement to see a tanks damage? And nash, admit it 2nd line recircs are beautiful but they waste energy magnificently. The real basis of tankless problems for Mfrs coming is ashore is the Americans who want 4-6-8-17 GPM hot water flow rates. NO WHERE IN THE WORLD BUT AMERICA DO YOU SEE THIS HIGH A FLOW DEMAND.
    Do people really need the 5-7 head human carwashes?
    And your 50gal gas tank it's more or less standard first hour delivery is 83 GPH. Flow more than 2 heads at 2.5GPM and you don't have much shower time. I love you folks with your 6 min shower.......ever had a teenager or two?
  20. MechGuy

    MechGuy Plumber @ Mechanical Contractor

    Messages:
    9
    Location:
    Iliinois
    Sorry but...

    You guys just don't get it....A Buderus and a indirect isn't a normal tank. It's really a tankless with an alternate heat source.
    No 100-125 gal or less residential tank will produce 240-268 GPH. Don't muddy the waters comparing apples to pomegranates.
    Also you're going to have to temper that production at anything above 125F as you can't legally deliver residential hot water over that temp.
    And fess up on that Buderus if it's a GB142 or such that's a $4000 equipment cost you seem to overlook although the indirect does help wring cost out of the whole set up.
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