Demand Water Heaters/ DWH/

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andyprius

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I'm curious what you professional think: I have seen and used them in Europe where Point of Use (POU) was right where you were, a DWH for the kitchen, another for the bathroom, etc. They worked fine. They were controlled by the volume of H2O, you want it hotter, you decrease the flow slightly. My son installed one at his house in CA in the garage and it doesn't work worth a damn. When taking a shower if you want to lessen the water flow, chances are it will get cold. So the only way to adjust the valves is wide open on the hot and then adjust the cold for a comfortable temp and then leave it there..I think the main problem is that it is not POU but located in the garage and has to run quite a distance even to get hot. So instead of saving money (as in Europe) the DWH is actually wasting energy. He likes tho, says it's elegant and it's his house.
 

Richnj

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on demand response

Im not a plumber but own an on demand system made by aqua star.. I think its great! It does take a little longer to make the hot water but its worth it. It sounds like he located the heater far from the house fixtures. That will take even longer. But as far as it wasteing energy - no way! Your water heater makes hot water several times a day wether you use it or not. On demand only when you need it. And a point of use w.h. is a different animal as it is not central. You will find more people switching to them. Also you can remotely set the temperature from a keypad in the house and get an immediate temp change. Just watch what size unit you buy in relation to how many fixtures you need to run at once. Maybe he has to small a unit.
 

Master Plumber Mark

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they are junk

they are nothign but trouble....

this will start a rageing debate, but

basically even if the unit does work ok you judt dont know

for how long..... and who can serivce it down the road and how quickly

they cost about three times what a normal unit ocsts

you have to de-lime the coil every year

you cant run more than one fixture at a time


and god help you if you need it serviced


here are some fun links

http://ths.gardenweb.com/forums/load/plumbing/msg0114073621251.html


http://www.askthebuilder.com/451_Tankless_Water_Heaters_-_Some_Surprising_Facts.shtml
 

Jadnashua

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A good hot water tank for an indirect system will only lose about 1/4 degree per hour, so it may not even turn on again for the day once it is hot. There is a big difference between types and their efficiencies. Plus, they require less maintenance and you don't have to worry about the water being too hot in the summer when the incoming water is warm or not hot enough in the winter when the incoming water is frigid. They are more forgiving if you live in a warm climate since your incoming water is likely always moderately warm. Plus, you can get whatever flow your pipes will supply...not the restricted volume required to allow the tankless system to heat the water as it passes by. This can make a huge difference if you want to fill a tub or for that occasional clothes washer load you want to be hot.
 

Cass

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No Demand

I have installed and uninstalled them. Like Mark said, wait until you need to service it and try to find someone.
 

Jimbo

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Lots of love and lots of hate for these. There is a ton of information available for research, on this forum, and elsewhere on the net. I suggest you read as much as possible and decide what the answer is for your particular situation.
 

Richnj

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Think again

My on demand system is the only way to go in my situation, I have a whirlpool tub that needs 80 gallons to fill it. There for i would need an 80 gal. water heater for a tub that i only use once in a while. There no way thats practical. If you get a big one mines 5.3 gal/min it will run 2 fixtures at a time. It will fill my tub in 20minutes and i have the ability to adjust the output temp. up when filling the tub to create more water volume by then adding more cold. As far as service parts are availible and the keypad is a trouble shooting aid. Sensors and circuit boards are availible. Or it can be sent back if you must. It is like any other high tech device. For me its the best thing going. Plus it should last 15-20 years(no tank to rust out) so the cost is worth it. What ever you get there will be a downside.
 

Richnj

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ps

Servicing a demand water heater is the same as serviceing a furnace. A computer and sensors. Like your car. It even diagnoses itself. They get fixed in the field so can demand heaters.
Its just that its new (in this country) and professionals are afraid of them, After a while people will feel more comfortable with them and get to know how to fix them. Of course like any other high tech device people will only service the brand the sell and install. There are pros and cons to everything and theres far less with demand water heaters than the old (simple tank jobs) that reheat the same water over and over again.

I know there is nothing simpler than a tank with elements and a thermostat but as odwh become more popular the cost comes down efficency goes up and they will be everywhere and even required someday! Also theres a new device on the market to speed the hotwater and cut wasted water while waiting for hotwater its called the chilipepper pump- www.chilipepperapp.com
Another advantage to odwhs. They have been used in other countrys for 25 years and they dont have many problems according to internet research. You younger plumbers had better learn about them! You old guys probably wont bother but thats typical. Now i think ill take a hot uninterruppted shower ( because i wont run out of hotwater!)
 

Master Plumber Mark

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I want to learn--please teach me....

I really want to learn about how to repair them......

where do you go to do this????? Do any of the people that are
selling them have any crash courses in this subject????

I am sure that their is big money in this because you
will be the only guy in town that knows how to do this...

and you will literally be able to charge anything you wish to.....

I could make the people sign a service contract with me
to come out every year and DE-LIME their units for
$300.00....thats not too bad...


I would guess that if that circuit bard goes bad
its gonna cost a pretty penny too....500+ labor........


--------------------------------------------------------------

So who do you call when that 3500 tankless water heater
goes bad, how do you diagnose them....


where do you get classes in repairing any of them???

I think I might call Bradford White just for fun...or A.O.smith and
see if some clean cut sales rep will come out to my
business and give me lessons in this.....



Right now thier is literally no body out there inour town
that knows how to service them, and my guess is most
people arent willing to wait 10 -15 business days for parts


Thats another angle I could take as a tankless reapirman!!!!!!

once they see that the parts are gonna
take three weeks to arrive and cost more
than a conventioinal water heater I will most likely
have a sale in changeing out the unit for a
50 gallon Brad White........!!!!!!!!!!

they will realize that it is cheaper than
going to a hotel for showers...




their is a silver lineing in every cloud,
all ya got to do is look for it....
 

Bob NH

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People keep referring to the use of demand heaters in Europe as though that is some justification for their use.

I have used the showers with demand heaters in Europe. They go to extremes to save energy. The demand heaters give lousy showers because the can't keep up with a satisfactory flow.
 

Jadnashua

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These things have the potential of saving energy, but even with today's energy costs, it will take a long time to break even, if you ever do. They require regular maintenance, and if you don't perform it, they will decrease their efficiency and the amount of hot water they can produce.

If you size it for significant flow, you'll be buying a very large unit, and may require a bigger gas main, piping, and significant flue, or a major increase in electrical service. Just 2.5 gallons per minute needs nearly 100K btu or more, depending on the input water temperature. Try filling a tub or a washing machine. If you have one thatcan actually handle a large flow (they all come with a flow restrictor which can make your shower less comfortable), when you run a little bit in the lavatory, if you don't have a tempering valve to moderate the temperature, you may end up with water extreemely hot and then scald yourself. At least one brand modulates the heat output to try to match the flow, but it still can create problems. That adds to the complexity, and therefore the cost to keep running or repair.

Comments have been made about the water heater having to run several times during the day to keep that tank hot. Well, thatmay be true, but not necessarily. Depending on the tank and how well it is insulated, that may not be the case. If you happen to have a boiler, using an indirectly fired hot water tank relies on the boiler for thatheat...some of them are in the mid-90% efficient range and the better tanks are rated at a loss of less than 0.25 degrees per hour. That's 6 degrees drop over an entire 24-hour day...it may not even turn back on.

A tank type of heater matches the more common US usage patterns, is cheaper to buy, install, and maintain. Spend a little bit more for one that is well insulated. You'll come out ahead, and be more comfortable in the shower, and your washing machine and tub will fill faster, too.
 

Mikey

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The Chilipepper pump...

...seems to work. I installed one in the kitchen last night, and darned if it doesn't work as advertised. My wife loves it. It's a little noisy, but not objectionable, and I'm sure could be quieted down with enough junk stored under the sink to cover it up. I've got another one coming for the master bath (at the other end of the house).
 

hj

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heater

ALL tank heaters are basically insulated the same, and if you put your hand on the jacket you will find that you don't really get a burn from the heat loss. In fact a heater can sit idle for a day or more before it turns itself back on to reheat. None of them actually go on and off several times a day. You have to sift through the hype for tankless heaters, and the "bashing" of both types.
 

GoingTankless

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Tankless water heating

It seems many of you are quick to bash the things you know least about. After reading many many posts it has come to my attention that what is lacking the most is an education in Tankless heaters.

I have installed hundreds of these units for home heating (radiant,hydronic systems and hot water coils) and also for domestic hot water.
Its a shame that the Master Plumbers keep bashing such incredible technology. There are many options that are available for any application.

Tankless heaters work. Plain and simple. Installers that are not taking the time to learn or simple just installing them wrong are very quick to say they don't work. I won't bore you with the pro's and cons of tankless and tank type heaters but if there is a system out there that could give me endless hot water, save me 30% to 50% on my fuel bills and not worry about flooding out my basement or damage cause by leaking tanks, and not to have to worry about the bacteria in tank type system, I'm for it.

My system in my house handles 5 full bathrooms, my heating for the house, my radiant heat for the garage and snow melt for the front and back side walk.So please don't say they don't work.

America and Canada are the only tank type heating countries. The rest of the entire world uses Tankless. Point of use and on demand systems.

These tankless units are also able to handle any commercial application. How does 4 million BTU's sound. I think they can handle the job.If you take your time and educate yourself on Tankless systems you will be amazed by the technology.

Did I mention they can last 20 to 25 years. Since all these parts are replaceable you never have to replace the units.

Do your home work. You will be a better plumber and you can offer you customers so much more.
www.boschhotwater.com
 
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Master Plumber Mark

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if what you say is true......

how come all these people are pissed off and dissapoiinted with Bosch??


http://www.epinions.com/Bosch_AquaStar_125B_NG_Natural_Gas_Tankless_Water_Heater/display_~reviews



http://www.epinions.com/Bosch_Natural_Gas_Tankless_Water_Heater_Aquastar_250SX/display_~reviews

looks like 80 % bad...


how come you had such gooood luck with them????

I have done a lot of homework on this subject fella.....

http://www.weilhammerplumbing.com/houseofhorrors/



you arent telling people the whole truth......


like how often are you supposed to de-lime them???
 
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Cass

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Hey GoingTankless

What part of the country do you work in as a plumber?
 

Dunbar Plumbing

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New Jersey

His one page website is loaded with info

Hey Cass, I've worked as high up as Butler county, and most recently Ward's Corner and Batavia, you close to any of those locations?

I did work up at a UDF in Dayton, broken water line right in the meter pit where it flares to the meter bracket. This was years ago and two of us made a grand out of a 1 hour fix. Wasn't me called the shots. Apparently it was something that had to do with the company I worked with, which of course is now out of business.
 
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Cass

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East Gate/8 mile Is about as far as I like to go, though I have been further, Wards Corner often, I cover Warren and Buttler mostly. Coffee some time?
 
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