what i meant to convey is that tankless has 1/2'' waterways with lots of bends.
the heat exchanger is what's going to fail.
we already know recirc lines fail due to oversized pumps, running 24/7, lack of reaming, turbulance.
mix that with a heat exchanger that's 1/2'' with a blow torch of a burner running on it.
Good point, Rick. Perhaps Navien's condensing technology with it's recirc tank built in (once it's debugged), Eternity's stainless heat exchanger tank, or some other bright idea will be the answer to both the technological and American mind set problems. I just hope the solution comes sooner rather than later.
I tell my customers that the technology has not caught up with the idea yet. most people want to save money not energy, no matter how green they are. tankless is not the answer yet.
Clark County Plumbing And Drain
Thank you for your reply. It was exactly what I wanted. Please do not take offense.
Those of us who have dealt with tankless problems go through this tango. I have dealt with three different manufactures of tankless and your replies sound exactly like the people I talk with on the phone.
Try this, maybe that, could be this, call me when you do that. That sounds ok but when your the guy at 7:00 on a Saturday night and the owners are hot it is no fun. Telling them you will order a inducer motor Monday because the supply houses don't stock repair parts is a good time. It is not a training issue either. Manufactures are constantly changing the board and sequence operations and voltage ranges on these unit.
The fact is, plumbers are the ones holding the bag on this. Manufactures blame plumbers for everything from venting, gas lines sizing, bad electrical, water quality, add a point of use, install a recirc. loop, water line sizing and the list goes on.
You mentioned venting is nothing new here, I disagree. Those exchangers have smaller inlets/outlets/tubing and when placed on a outside wall with a steady wind it can freeze in no time via the vent. Also their are restrictions on venting when a pool or hot tub is in close proximity. Some units have inducer motor speeds set very low to help with energy conservation. Negative pressure on the vent causes the unit not to vent properly and then shutting down of course in the middle of a shower, due to over heating.
Tankless manufactures like to talk about how they have been used in Europe for so long but they don't talk about how differently we live and build. Smaller homes, tankless units are installed in the bathroom, temps set on those units are set so that when they take a shower they just turn the hot valve all the way on and no cold is used. Lower temps set on tankless substantially increase their life span. It is a whole different game.
Just look at venting:
Rinnai, Noritz, Bosche just to name a few all use different material, sizing and types of vent. Good grief. I'll just stick with my 40 gal. natural gas for 300.00 bucks.
Warranty: Lets say I find that a customer has installed the unit in the wrong location and needs moved to make it work. Not only do they have to pay me for replumbing and venting it, they also get their warranty voided. Not cool.
Don't get me wrong here, I love technology and new things but in the case of tankless, until things change, the customer and plumber loose on this.
Anyone can tear a man down, few can build one up.
I have not seen a residential customer that needed endless hot water. Ever. They need the adequate amount for their lifestyles and the fixtures therein.
I have not had any complaints from installing a properly sized/installed tank heater. Not even lack of hot water. Ever.
Tanks are WAY more flexible, perform fine with less maintenance, and give the customers what they want without some of the drawbacks involved with tankless models such as cold water sandwiching, flow rate requirements for them to activate, and power requirements.
Most residential customers stay in a home less than 7 years last I checked making any small monthly savings redundant vs. cost of investment for installation and the interest lost on that cost. In short, if you're looking to save money, it's currently a stupid "investment" in the U.S. Only places I've seen where sq. ft. payback comes into play are places like London where some real estate was bringing $10,000.00 sq/ft.! Prices can change though. If you want to gain some room, put a tank in a hut.
All of the tables I've seen will give you a temp degree rise & gpm produced at that rise. But they will not give you the winter temperature of incoming water at each installation that you're going to encounter. Some water lines' shallow burial depth can make incoming water be around 50 degrees or even lower. To put that in perspective, some tankless units that are rated for 2 to 3 bathrooms at 199,999 btu's would only give you around 4.3 gpm at the required 77 degrees rise. That's less than 2 flow restricted showerheads. I highlight winter temperature as this is the most taxing time on water heater systems and that is the point where everything should be calculated or you're going to get callbacks or complaints. I don't do well with either. That's why I favor tanks.
I won't even touch on the redundant stupidity of circulating lines & some of the diagrams the manufacturers provide.
The people that I've encountered that "love their tankless" usually adjust their behavior to accommadate it's output or to justify their "educated" decision.
Onceandforall, I do hope you stay as I and others might have questions you can answer regarding some of these things that we're going to run into. Are you a tech person for Rinnai? Noritz? others?
But I have to say it's a little presumptious for someone to come into any public forum early on and start a thread assuming they are the authority on anything.
Last edited by BobsPlumbing; 03-08-2009 at 08:40 PM.
Plumbus, I spent the day yesterday with the eternal factory rep. Amazing unit. Absolutly nothing like the current spate of crap that is on the market today. Whole lot more money though. The amount of water these babies will deliver is staggering. Then again, the technology is not particulary new.
I'll tell you what though. I am damn tired of the Rinnai, Noritz, Tagaki and all the other guys touting thirty year old technology as though it was the second coming. I agree 1000% with Rick. These things are going to be the lawsuits of the very near future. (along with pex) (another veiled hi-jack attempt)
I would agree, not a good time. It's strange to me that supply houses in your area don't have parts......damn near every supplier i speak with asks about repair parts.....no ones to blame in that situation but the factory sales person for not making that part of the stocking inventory.
Sometimes that is the case, sometimes the company are at fault. But the "blame the plumber first" is NOT a standard practice with most companies. But to be fair, i've seen several units that the plumber ripped off the wall because it wasn't working only to find out that they never checked and cleaned the filter.
Sorry I was a little vague on that one.....I was referring to venting into head winds as being nothing new. Good point though.
the lower temp issue is dead on. That is why there is so much problems with calcification in the by-pass type of tankless. the heat exchanger is anywhere from 250 to 400+ degrees. Use the ones that don't use this technology.
how much are you paying for 40 gal. direct vent these days?
How does moving a heater void its warranty? If you have been up against this before....I'd suggest not telling them you moved it.
Thanks for sharing this post. I'm not trying to sell anybody anything they don't want to buy.....the intent was to help anybody if they had any questions. But it seems I may have been the rabbit accidentally running into to dog pin trying to escape cat.
If you need any help finding temp rise charts let me know...everybody has them. See if the ones below are the type you are looking for.
And yes you can run multiple showers in the winter time....I can give you some numbers of people in Buffalo if you wish...they have the coldest water is the country, IMHO.
I believe you may have mistaken my intentions.