You're right about the long runs, but I'd argue that a PEX remote manifold, if located/done correctly, should improve your delivery system even in those cases. As I said in the beginning, easier to do in new construction, mostly difficult, and usually expensive to effect in most retrofits ... which is why it isn't often done, and IME results in the biggest cause of user dissatisfaction with tankless installations.
Close to the endpoint (your "right at the tap") is pretty much how Europe has operated for decades, and very successfully. Pumps and a loop system, if properly implemented, also seem to work very well, although I haven't built one that way personally.
You're right about the long runs, but I'd argue that a PEX remote manifold, if located/done correctly, should improve your delivery system even in those cases. As I said in the beginning, easier to do in new construction, mostly difficult, and usually expensive to effect in most retrofits ... which is why it isn't often done, and IME results in the biggest cause of user dissatisfaction with tankless installations.
Close to the endpoint (your "right at the tap") is pretty much how Europe has operated for decades, and very successfully. Pumps and a loop system, if properly implemented, also seem to work very well, although I haven't built one that way personally.
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I could see using a low temperature preheat (maybe NG or solar) to take the edge off the initial water heating and then a small (maybe electric) booster to give the final temperature at the faucet. Probably too much installation expense though.
I have many of my runs disconnected from my hot manifold to keep more frequent circulation going in the trunk runs. I was waiting so long for hot water it was painful. I want to put my air handler on the end of that run yet, to keep hot water close to faucets, except it will not help in the winter and the legal limit of 60C makes an upstairs warm-up each morning a little too lengthy. I did add it to the feed of the manifold and that cut a few seconds off the time delay. I still have access to most of my PEX as the basement ceiling is removable tiles or open. Not done experimenting yet.
The PEX really puzzles me over my old house copper system. I have less length to the farthest faucet, and the PEX is supposed to be smaller ID and it still seems to take double the time the copper house did for hot water to hit the end faucet??? Maybe I am just watching too closely. It also seems to cool off much faster than copper pipe so you start with room temp every time. I was thinking it should be the other way around. Meanwhile a neighbour installed all copper and a circ pump and has hot water within 2 seconds anywhere. GRRRRR...
Watch that paraphrased Google knowledge, it'll bite you in the butt just like your plumbing salesman ...
Water temperature and source makes no difference to a manifold delivery system itself, hot or cold, tank or tankless.
With a PEX mainfold system, properly located and installed, the water in the usual 3/8" tubing has a higher water velocity, and the water, hot or cold, is delivered much faster than with a conventional piping system, tank or tankless, and with a lower volume in the tubing ... albeit not much more "green" on that score.
Once again, proper planning and installation to the forefront. ====================
The tankless water heater problems are not addressed with design techniques of water delivery systems. Hot and cold water have different requirements for delivery. Cold water can go to Timbuktu and back and there isn't much ill effect on it. Hot water needs to be delivered before it cools off.
That may be the biggest problem with this stuff here. 1/2" is the standard and 3/8" is very uncommon and more difficult to obtain. There may even be a code issue as PEX is new on the scene.
We do not use 3/8" tubing. We only have 1/2" PEX pipe used for plumbing. Plumbing uses pipe sizes, not tubing. 3/8" PEX pipe could make more sense to fill less reservoir with hot water before delivery. I am not familiar with an code issues on the smaller size.
I only know the latest system delivers hot water much more efficiently without the manifold and longer lengths of reservoir.
Disagree... they can be, and they should be if you have the opportunity to do so.
That's not what you said ... You specifically state that about a manifold system, which I have proven in practice to not be the case with proper attention to detail.
A 1/8" diameter difference in pipe is significantly and mathematically different as far as flow and volume characteristics.
The tail that wags the dog with diameter is the fixture requirements ... There is not a one size fits all that will cover all bases and make everyone happy.
One of the jurisdictions I build in does not allow PEX ... It is why I'm so painfully aware of the differences in tankless delivery that are possible with a PEX manifold system when called for.
Every plumbing situation is unique (even in tract homes with supposedly identical plumbing schemes) so the above is not surprising.
Again, the toughest thing to get correct is tankless in a retrofit/remodel, much easier to design, install, tweak in new construction, there are simply too many shoe merchants and ribbon clerks in the game, and even plumbers will not agree on much of it.
And again, it is why I do not have tankless in my own home to this day, which I built before the technology was readily available locally.
That said, the next new house, and the ones after that, that I build will more than likely be spec'd for tankless as long as it is in a jurisdiction that allows me insure that a design for that particular and unique situation can be forthcoming, and that it will satisfy me, and the customer ... anyone who knows me will attest to the fact that I abhor callbacks.... Nuff said.
Did you ever go back, as a check, and re-spec your house as if were a new installation?
I don't think they were strictly for builder accounts, but my suppliers had downloadable spreadsheet based software that would allow you to put in all your parameters, ambient ground water temps, list all bath and kitchen fixtures and their flow requirements, etc., and spec a general idea for a recommended tankless unit.
Might give you a start point in sussing out the reasons .... Just a thought.
Circulating pumps would seem to defeat any effort to reduce power usage as they keep sending hot water around the loop to cool and then be reheated even when there is no usage so instead of wasting one pipe full of cold water that heat is being lost all the time. Of course the water is saved but the heat (heating power ) is lost. Choice is on the user I guess.
Did you ever go back, as a check, and re-spec your house as if were a new installation?
I don't think they were strictly for builder accounts, but my suppliers had downloadable spreadsheet based software that would allow you to put in all your parameters, ambient ground water temps, list all bath and kitchen fixtures and their flow requirements, etc., and spec a general idea for a recommended tankless unit.
Might give you a start point in sussing out the reasons .... Just a thought.
Disagree... they can be, and they should be if you have the opportunity to do so.
That's not what you said ... You specifically state that about a manifold system, which I have proven in practice to not be the case with proper attention to detail.
A 1/8" diameter difference in pipe is significantly and mathematically different as far as flow and volume characteristics.
The tail that wags the dog with diameter is the fixture requirements ... There is not a one size fits all that will cover all bases and make everyone happy.
One of the jurisdictions I build in does not allow PEX ... It is why I'm so painfully aware of the differences in tankless delivery that are possible with a PEX manifold system when called for.
Every plumbing situation is unique (even in tract homes with supposedly identical plumbing schemes) so the above is not surprising.
Again, the toughest thing to get correct is tankless in a retrofit/remodel, much easier to design, install, tweak in new construction, there are simply too many shoe merchants and ribbon clerks in the game, and even plumbers will not agree on much of it.
And again, it is why I do not have tankless in my own home to this day, which I built before the technology was readily available locally.
That said, the next new house, and the ones after that, that I build will more than likely be spec'd for tankless as long as it is in a jurisdiction that allows me insure that a design for that particular and unique situation can be forthcoming, and that it will satisfy me, and the customer ... anyone who knows me will attest to the fact that I abhor callbacks.... Nuff said.
================ All that preaching from you we will see when you actually have some experience with one and your well thought out design. I am sure they improve them each new model and that may help some. I have noted changes from the manufacture, in my conversation with an Engineer today, to help these problems, somewhat.
Right now I have to improve my venting as the seven foot high snow drifts choke it off in the winter and it is not reliable as a heating source. I am debating to just replace it with a tank style. It's been a nuisance and, again, installation of the water delivery system has nothing to do with it any of their inherent problems. Even the manufacturers show methods to add tanks and circ pumps to alleviate their known inherent problems. No delivery system design techniques are involved.
Circulating pumps would seem to defeat any effort to reduce power usage as they keep sending hot water around the loop to cool and then be reheated even when there is no usage so instead of wasting one pipe full of cold water that heat is being lost all the time. Of course the water is saved but the heat (heating power ) is lost. Choice is on the user I guess.
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Definitely! except in the winter the heat displaces some home heating needs anyway. and costs nothing. Our NG is much cheaper than elect. anyway.
Either N.America will take a step down in their standard of living, down to Europe's standards using tankless, the tankless will improve from years of development in Europe, or disappear as a bad sales joke to extract money from our pockets.
Here is one manufacturer's solution. Check out page 33
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a tank for your tankless water heater. Now you can spend the money over and over again!
And it costs him $40/mo for the extra electricity or gas to do that.
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Apparently the costs are very small. If you listen to the sales people it saves money on water bills not running the taps to get hot water up from the depths of hell. The units have timers on them and additional heat in the house costs nothing in the winter.
And it costs him $40/mo for the extra electricity or gas to do that.
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Apparently the costs are very small. If you listen to the sales people it saves money on water bills not running the taps to get hot water up from the depths of hell. The units have timers on them and additional heat in the house costs nothing in the winter.
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is a newer unit that has circulation pumps and controls built right inside the unit. Also a hi-efficiency unit with condensing heat exchangers. Looks like a newer and more modern unit than the Rinnai (supposed to have been top of the tech. at the time) I bought two years ago.
I've installed seven whole house tankless units in the last three years with none of the problems you're experiencing ... and you, how many?
Your data set, and your ignorance are both showing ...
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You admit, after all the authoritative hype and issue avoidance , you have no experience using or owning a tankless unit??
Despite multitudes of complaints about the same problems from actual experienced people, you classically blame the installer. Classic salesman BS, right on cue. My guess was correct right from your first empty defense.
I don't need to return any insulting comments for that one. It speaks for itself.
Again, best of luck with your sales hype. There are some better units available coming on the market.
You have my vote. Besides I have seen some excellent trends in rock and shrubbery projects replacing lawns. Many of those are because the Province has outlawed weedkiller fertilizers. Thank goodness we're still allowed our banana trees.
-------------------------- They are finally getting that idea in place for your old stomping grounds of SoCal which is little more than a paved desert.
Green grass in the English country side is one thing, in the desert SW, quite another.
Water rationing for lawns is in place as well as inncentives to rip out grass and return to the native SW ground covers.
Let's recap .... Based on your own words you have experience with one installation; an installation which you publicly admit was based on "plumbers BS" and "salesman hype", and for which you admittedly fell; an installation that subsequently doesn't work (big surprise); a faulty installation for which you have repeatedly failed to find a solution; and, despite a public litany of your own failed efforts in that regard, you have somehow deluded yourself into believing that you possess a superior knowledge of the technology, of how to make it work, and that the design, planning and/ or installation of same is somehow not at fault??
Good luck with that line of self delusional reasoning, Bubba ... you'll need all you can get.
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