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Community => Non-audio hobbies and interests => Home Improvements and Renovations => Topic started by: jtwrace on 4 Feb 2011, 05:38 pm

Title: Tankless Water Heater
Post by: jtwrace on 4 Feb 2011, 05:38 pm
Who has one and what do you like and dislike? 

Please mention the brand. 
Title: Re: Tankless Water Heater
Post by: ArthurDent on 4 Feb 2011, 06:22 pm
I've got a Rinnai 'on-demand' gas unit. Had it installed 3 years ago along with a direct vent gas fireplace insert. I had a major roof remod at the same time so with the added insulation it's a bit difficult to address the exact cost savings. Given my place was previously all electric with baseboard heat (not the most efficient), initially I saw a roughly 25-30% monthly reduction in the electric usage portion of my bill for the first year. The combined bill was still a little smaller than the prior electric only. That year there was a 15% increase in the gas charges, and there have been a couple of additional increases since in both electric & gas rates. The bill has remained pretty stable, and I have no doubt I'm saving over what it would have been without the changes.

Up front cost is a lot bit more than sticking with a tank, and it's definitely not for everyone. A Mech Engineer friend ran a cost analysis on his family/house, and figured for a family of 2-3 it would take at least 10 years to recoup the cost difference.  So if you are looking short term it's not cost effective. 'On demand' is also a very relative term. It takes probably at least twice as long to get hot water to the spout as it does with a tank. However, once it's there you can take all day showers without fear.

Other factors in play are your geographical location, which dictates the base temp of the water you are pulling thru the supply system. Tankless units are sized based on rate-of-rise/flow temps, so the colder the start temp the longer it takes to heat and the lower the top temp it can raise things. Configuration of your house also enters, with regards to how far from the unit to the farthest bath. There are small auxiliary units that can be added under the sink if you really want hot water right now.

Negatives - up front cost, the added wait for hot water, though I'm single so don't mind washing my hands with cold water most of the time.

Positives - I do like that I don't have to worry about running out of hot water, flushing the tank each year or so, and replacing a tank every 5-10 years. Which is probably above average due to single usage. In my case I also think there is enough savings to justify the up front expense since I'm most likely stuck for the long haul.

You might do a search of the archives here as there was another thread on the topic a couple of years back with a fair cross section of opinions & information. Note that this is for a gas unit, with electric YMMV. Hope this helps.
Title: Re: Tankless Water Heater
Post by: jtwrace on 4 Feb 2011, 06:34 pm
It takes probably at least twice as long to get hot water to the spout as it does with a tank.

A tank or a tankless still has to travel the same length of pipe from where it is mounted to the water outlet that you are standing at waiting for the hot water. If that run is 75 feet, then you are going to have to wait for 75 feet of water to clear out the faucet for the hot water to get to you.





Title: Re: Tankless Water Heater
Post by: Steidl Guitars on 4 Feb 2011, 06:39 pm
I have a Bosch tankless, gas.  I love it, but it's not for everyone.

And Arthur is right -- you do have to wait a bit longer for hot water than with a tank.  The tankless sends water right away, but it takes a few seconds to fire, so that's the difference.  Like him I am happy to use cold water for short-duration tasks.

I just installed an efficient dishwasher that doesn't draw enough to kick the unit on.  To get around that, I run the hot water in the sink for a minute or so (so much for high water-use efficiency!).

Still, I love not having 40 gallons of water sitting there being heated and not used.  So it takes more effort to use than a tank, but it's efficient and almost zero maintenance. 

Title: Re: Tankless Water Heater
Post by: ArthurDent on 4 Feb 2011, 06:44 pm
A tank or a tankless still has to travel the same length of pipe from where it is mounted to the water outlet that you are standing at waiting for the hot water. If that run is 75 feet, then you are going to have to wait for 75 feet of water to clear out the faucet for the hot water to get to you.

True, but with a tank the water flowing comes from the stored already heated supply. With the tankless unit (as I understand it) there is a control valve that slows or restricts the 'hot' water flow until the water is brought up to a certain temperature before it allows a full 'hot' flow. Hence the added delay. As noted the twice as long is in my location, outside Seattle. It would probably be much less in more southern locations, or possibly longer in colder climes. When doing my initial research I was told for places like Colorado it generally takes more than 1 unit to get the job done (2 units in series) as the temp range the water must be raised is quite a bit more.

And 'no', you don't see a reduced flow at the faucet, I believe there is a by-pass that sends make-up flow until the unit reaches temp, then the by-pass shuts down.
Title: Re: Tankless Water Heater
Post by: jackman on 4 Feb 2011, 07:04 pm
When I needed to replace my hot water heaters, I looked into tankless but it was not a good option in Chicago.  Three different companies said they would install them but cautioned about what to expect in the winter months.  It gets extremely cold in Chicago during the winter (it's 19F now but will be in single digits next week) and tankless heaters will not give sufficient water flow (or amount of hot water) in this climate.  There are other options (new efficient tank systems) you can look at if you are in cold climates but I don't think tankless will work for most people in this area.

Just wondering.  My info is about three years old.  Has anything changed?  The guys I consulted would have gladly installed the new tankless heaters.  In fact, they would have made much more on the deal but they said they were tired of complaints.  Plus, if you have mineral deposits in your local water supply, tankless systems are prone to clogging.  Is this something any of the tankless system owners have experienced?  I was disappointed but feel good about my decision.  Were there options I did not consider? 

Thanks!

Jack
Title: Re: Tankless Water Heater
Post by: ArthurDent on 4 Feb 2011, 07:28 pm
From what little follow-up on the technology I've done I don't think anything much has changed jackman. Good point on the composition of the water as well. I'd forgotten about how 'hard' the water I grew up with in Indy was. So far no problems with that after my 3 years. Not 'soft' by any stretch, but not nearly as bad out here. Sounds like you talked to the right folks for your situation.

Since you mention it I'll check with my installer on whether we need to do a maintenace check on mine. Thanks for the reminder.
JD
Title: Re: Tankless Water Heater
Post by: bacobits1 on 4 Feb 2011, 07:34 pm
I looked into it last year. They wanted $5k !!!!!!!!!!!!!!
Now the heater itself is about $900- $1200 on average.
Where is the rest of the money going? An extended warranty etc.
I already had gas. What BS!

The only way this may be viable is an install when the house is built.
It can get a bit fussy on venting too.

Read below what consumer reports says.

http://www.consumerreports.org/cro/appliances/heating-cooling-and-air/water-heaters/tankless-water-heaters/overview/tankless-water-heaters-ov.htm

When they asked me why I decided against it I just told them to read the above article.


D
Title: Re: Tankless Water Heater
Post by: jackman on 4 Feb 2011, 07:42 pm
Thanks Arthur.  I'm far from an expert and really wanted to go with the greener system but the drawbacks related to geography put me off.  The plumber said in areas where the water had high amount of sediment (like my area), the small arteries or tubes (don't know tech term) in the tankless heater could get clogged and restrict water flow.  The whole house tankless systems (in my layman understanding) work by sifting water into small tubes, creating more surface are that can be warmed up quickly.  These tubes (according to the guy - he may be wrong!) are susceptible to clogging over time if your water has sediment.  Also, if water entering the system is too cold, it takes longer to heat it up and the flow is much slower than comparable tank systems. 

I hope someone has a different experience because I like the idea of tankless and the savings they generate! 

Cheers,

Jack

Title: Re: Tankless Water Heater
Post by: Carlman on 4 Feb 2011, 08:03 pm
Do you really think a hot water heater has a tankless job?  ;)
I know I appreciate what my water heater does...  :roll:
Title: Re: Tankless Water Heater
Post by: ArthurDent on 4 Feb 2011, 08:13 pm
Thanks for the link bacobits, good & definitely valid info (particularly the life-cycle costing numbers). And yes, sounds like someone was looking to stick you pretty good. My local utility supplies both electric & gas service. I got the gas service for free since they have been pushing that for some time to reduce the electron usage. That was dependent on doing both the heater & insert, as the insert qualifies as a heating device (& does the job very well). I barely use the baseboard any more, and not at all in the living/dining/kitchen area.

Since my HVAC folks ran the gas line from the service on one end of the house to the other thru the crawlspace for the insert, with a feed to the heater, and another capped for future gas stove I can't break down the individual run costs. But even with the '0' clearance vent thru the roof installation it wasn't anything close to what you were quoted for just the tank. A buyer beware situation to be sure. Also as you note the vent can be tricky due to code requirements for clearance to any air intake, or window.

Note that I'm no expert either, just been in one end of construction for close to 40 years and have access to some honest knowledgeable folks. I did a reasonable amount of homework back when I made the decision, and since I had changed my own tanks out twice didn't want to be bothered again now that I'm over 60.
Do you really think a hot water heater has a tankless job?  ;)
I know I appreciate what my hot heater does...  :roll:
good one Carlman    :lol:
Title: Re: Tankless Water Heater
Post by: srb on 4 Feb 2011, 08:25 pm
I also had looked into a tankless unit, but the extra installation expenses made me go with a conventional tank in the end.  The gas tankless heaters require a higher volume of gas flow and my 3/4" gas pipe run would have had to been replaced with 1" piping.  The hotter venting also required an expensive triple-wall stainless steel vent.
 
Electric tankless heaters also require a proportionate increase in energy for on-demand heating, and one I was looking at required two 240V 50A circuits.
 
Both types have an electronic control module, which for some has been a costly replacement when out of warranty.  They also require a minimum flow to kick in, so often a trickle situation like a tiny stream of hot water for shaving is often not enough to trigger heating.
 
So I ended up with a conventional tank and spent an extra hundred dollars for the best premium internal insulation option I could find.
 
Steve
Title: Re: Tankless Water Heater
Post by: jriggy on 4 Feb 2011, 08:35 pm
Hi,

 Sorry for not reading all the posts here in deatail but... We have a Rinnai R85. Have had it  for a few years now and I did not notice any performance changes at all. There are only two of us here w/ 1 kitchen 1 full bath and one half bath. In our home, if the water takes longer to get hot at the source location, it is by seconds. No noticeable change to either of us. Also no flow change at all...

We have the exact same water 'performance' and our gas bill went down! Ill havta ask the wife how much if anyone is interested. But I believe our budget went down 15 or 20 a month.
Title: Re: Tankless Water Heater
Post by: ArthurDent on 4 Feb 2011, 08:52 pm
More good info Steve. I looked up my original exchange with my ME friend and have corrected that post, his findings were for 2-3 people payback was 10 years not 5. (memory just isn't what it once was, sorry for the mis-information)

It was also mentioned in my friend's comments that whether the installation is on an inside or exterior wall is a factor due to the need for combustion air. The possible need for additional ducting or an extended vent will add costs as in the '0' clearance vent you note.
Title: Re: Tankless Water Heater
Post by: hometheaterdoc on 4 Feb 2011, 08:55 pm
I have a natural gas fired 50 gallon tank in a now 2 year old house... it's not in any need of replacement, but I've been considering tankless for the sole reason that taking a shower after the better half means cold water thanks to high flow heads in the master bathroom shower and her penchance for taking her good sweet time in there in the mornings...  it would almost be worth the cost just for that reason alone... I've been tempted to look into it but was concerned about the timeframe to recoup the upfront costs.  Thanks to everyone for the info... I'll look into it a bit more and see if it makes any kind of sense....
Title: Re: Tankless Water Heater
Post by: Steidl Guitars on 4 Feb 2011, 09:50 pm
If you don't want to be inconvenienced, a tankless is probably not for you. 

My tankless cost me about $600 a few years ago, and I did the installation -- I am no plumber. 

I hung it on the wall (~20 lbs.?), extended the gas line that was in place for the heater it replaced (screw fittings), added a few feet of copper pipe to connect with the existing inflow and outflow pipes, and enlarged the roof vent from 4" to 6" to handle the larger pipe (double walled spec'd). 

The unit I have requires no electricity at all; it has a wee turbine that creates the spark to fire the burners. 

Seems that electric units make the most sense only when located at the point of use, say under a sink, where you only need small amounts of hot water.  To run a whole house unit, we want fire and want it now. 

(http://www.audiocircle.com/image.php?id=42373)
Title: Re: Tankless Water Heater
Post by: twitch54 on 4 Feb 2011, 09:56 pm
having hot water baseboard heat (oil fired boiler) the domestic hot water coil is incorporated within. IMO, it works superb and it's one less item (hot water tank) that I have to deal with. I'm on well water and my original coil and boiler (builders grade) lasted almost thirty years.
Title: Re: Tankless Water Heater
Post by: borism on 4 Feb 2011, 11:42 pm
We installed a Takagi - Japanese tankless water heater ~ 10 years ago. It was about $ 1000. Fortunately, a friend installed it for free. I think Takagi is now sold under the Bosch brand through home depot. The greatest benefit is continuous hot water. We are a household of 4 and occasionally have a few guests stay over. In the past, with a hot water tank, we would routinely run out of hot water. I live in Connecticut and it gets very cold here in the Winter and so far there have been no issues related to flow-through water heating. Finally, the unit has performed without glitches so far. Only minor issue is that you can not run two showers in separate bathrooms at the same time. There is not enough hot water flow.
Title: Re: Tankless Water Heater
Post by: chrisw on 4 Feb 2011, 11:43 pm
We had a Noritz 751 model installed in January of 2008 here in the North Texas area and we've been very happy with it.

The up-front installation costs and requirements (large enough gas lines) are definitely a negative, but it allowed us to relocate the water heater from the attic (in the center of the house) into the garage - the city inspector explained they require a certain amount of space in the garage for a water heater, and our garage was 18" shy of meeting the requirements, but a tankless model was acceptable since it's a much smaller unit. I feel much better knowing if the water heater begins to leak, it would leak in the garage instead of into the ceilings!

When they installed the unit, they routed the controller into the master bathroom so we could set the water temp to say 105-110 and just turn on straight hot to fill up our jetted tub. One really cool feature it has is a flow alarm, so I set it to 30 gallons, turn the hot water on, and walk away. When I hear it beeping, I know the bath is ready. Also, setting it to 30 gallons reminds me that I've lost of track of time in the warm shower.

Hard water is definitely a concern, and I have to connect a bilge pump to the tankless unit and cycle 5 gallons of vinegar through it once every year to help dissolve some of the build up. Since the unit is in the garage now, this isn't a big deal for me.. when I had to climb up in the attic and connect a garden hose to flush the previous water heater, that wasn't much fun.

One thing I learned this week with all of the ice and snow in the Dallas area is if the gas supply pressure drops low enough (due to the high demand on the utilities), the unit will give up and throw an error code. Once I set it to a lower temperature and reduced the flow, it was able to keep up to provide me with 100 degree warm water.

Since we had additional piping added to relocate the water heater into the garage, it actually takes longer for the warm water to reach the faucets, and I've considered an under-sink electrical water heater just for the master bath since it takes about two to three minutes for the warm water to get to the faucet, but it hasn't bothered me enough to do anything about it quite yet.

Last year as part of remodeling the house, I started doing reading on shower heads and switched to shower heads made by a company who has been getting a lot of attention from major resorts for their low flow shower heads, Bricor (www.bricor.com (http://www.bricor.com)) We switched to a 1.5 gpm shower head in the guest bath, and a 2.0 gpm shower head in the master bath, and those have really paid for themselves in water savings.. the previous shower head was delivering close to 5.0 gpm and while it gave a good drenching shower experience, I can honestly say that the new shower heads deliver a solid "high pressure" shower experience.

Anyway, good luck with your decision!  :thumb:
Title: Re: Tankless Water Heater
Post by: Phil A on 5 Feb 2011, 01:12 am
I replaced mine with a conventional one 3 years back.  Someone I work with is about to do the same now.  They have become more commonplace than they were 3 years back but not as common as conventional hot water heaters.  There are still many reports of maintenance on some units costing more than conventional units.  When the A/C compressor went last year I bit the bullet and just got whole new furnace too as I figured I would have to do that 6-8 years down the road anyway.  I replaced the windows a year and half back from the builder's grade crap to something decent and that made a difference.  I also could have waited but figured I'd just grab the energy credit and bite the bullet since I had saved to so it and interest rates were low and I'd get a better return on energy savings.
Title: Re: Tankless Water Heater
Post by: Cheerwino on 5 Feb 2011, 01:41 am
Our house has two Microtherm electric on demand "thankless" water warmers. Both have been replaced due to plastic tank leaks (one has been replaced twice) in the five years we've owned them (they're probably eight years old now). Thankfully, they were covered by combination of home warranty and manufacturer warranty. But, we still went months without hot water while the warranties were in contention.  :banghead:

Once it leaks, the water shorts out all the microchip controllers and basically the whole unit needs to be replaced. The installers I talked to said to avoid tankless electrics and stick with tankless gas. We decided not to retrofit because there was no good place to put a standard hot water heater, although one could have easily been built into the house originally (we weren't the original owners).

I would not recommend Microtherm or an electric on demand water heater.  :cuss:
Title: Re: Tankless Water Heater
Post by: FullRangeMan on 5 Feb 2011, 01:46 am
I use one of these below, electric around 6K watts, the filament resistance last two years average and costs same as 5dollars, it provide instant hot water in 3 temperatures.
Of course for winter 120V model are a bit weak, but my house are all 220V, the 220V model are plenty of hot water in the winter.
This device are great value per money, and last for years, the instalation costs are none.
(http://img715.imageshack.us/img715/7890/chuveiroviadodajanete.jpg)
http://www.lorenzetti.com.br/portal_duchas.asp

Title: Re: Tankless Water Heater
Post by: ArthurDent on 5 Feb 2011, 08:11 am
I use one of these below, electric around 6K watts, the filament resistance last two years average and costs same as 5dollars, it provide instant hot water in 3 temperatures.
Of course for winter 120V model are a bit weak, but my house are all 220V, the 220V model are plenty of hot water in the winter.
This device are great value per money, and last for years, the instalation costs are none.
(http://img715.imageshack.us/img715/7890/chuveiroviadodajanete.jpg)
http://www.lorenzetti.com.br/portal_duchas.asp
Intriguing approach to the issue FULLRANGEMAN. Will have to search for US distributors, and info as I'm unable to translate. Have you always had this unit(s), or do you have cost comparison experience verses a standard tank type heater ?   :thumb:
Title: Re: Tankless Water Heater
Post by: djbnh on 5 Feb 2011, 10:10 am
having hot water baseboard heat (oil fired boiler) the domestic hot water coil is incorporated within. IMO, it works superb and it's one less item (hot water tank) that I have to deal with. I'm on well water and my original coil and boiler (builders grade) lasted almost thirty years.
We have the same set up @ my house. Plenty of hot water.
Title: Re: Tankless Water Heater
Post by: JLM on 5 Feb 2011, 12:07 pm
Using the home heating boiler for hot water is a low up front cost, but wouldn't running the big boiler in the summer be very inefficient?
Title: Re: Tankless Water Heater
Post by: JLM on 5 Feb 2011, 12:17 pm
Love the idea of the Lorenzetti, but it could be a real mess to retrofit.  In my five year old house (with 200 amp service and all 12 gauge/20 amp circuits) we may have enough circuit capacity, but to run wiring to 13 fixtures would be major.

And I rather like having a (power vented propane) heating source in our finished basement here in the great white north.
Title: Re: Tankless Water Heater
Post by: twitch54 on 5 Feb 2011, 08:16 pm
but wouldn't running the big boiler in the summer be very inefficient?

Not at all, on average it consumes about 12-15 gallons of htg oil per month to heat the domestic hot water. FWIW, my wife and I are 'mty nesters'
Title: Re: Tankless Water Heater
Post by: FullRangeMan on 5 Feb 2011, 08:18 pm
Intriguing approach to the issue FULLRANGEMAN. Will have to search for US distributors, and info as I'm unable to translate. Have you always had this unit(s), or do you have cost comparison experience verses a standard tank type heater ?   :thumb:
Dear Arthur,
I will translate the text for you, If you post here or send me by PM.

I feel there is various US brands of electric showers, or not??  IF are you saying there is no electric shower avaliable in US I am surprised.   The instalation of this shower are fast, no more than 30 minutes, to change the resistance are ever faster, about 5 minutes, no mess, a spare resistance sells for 3 or 4 dollars.

My actual electric shower cost me under ten(10) dollars and are 16 years old already. Seems to me a small gas heater price starts at 600 dollars here, only the heater machine. 
The special hot water copper tubes, and instalation costs are ever more expensives, and the quality of the service may not be great, as are need to hired people to install all this things.
Regards, Gustavo
Title: Re: Tankless Water Heater
Post by: Bill@LakeGeorge on 5 Feb 2011, 08:24 pm
In the upper right hand corner of the posted website there is a link to english.
Title: Re: Tankless Water Heater
Post by: ArthurDent on 5 Feb 2011, 08:32 pm
Dear Arthur,
I will translate the text for you, If you post here or send me by PM.

I feel there is various US brands of electric showers, or not??  IF are you saying there is no electric shower avaliable in US I am surprised.   The instalation of this shower are fast, no more than 30 minutes, to change the resistance are ever faster, about 5 minutes, no mess, a spare resistance sells for 3 or 4 dollars.

My actual electric shower cost me under ten(10) dollars and are 16 years old already. Seems to me a small gas heater price starts at 600 dollars here, only the heater machine. 
The special hot water copper tubes, and instalation costs are ever more expensives, and the quality of the service may not be great, as are need to hired people to install all this things.
Regards, Gustavo
In the upper right hand corner of the posted website there is a link to english.

Thanks, and Thanks, FRM - Bill. I missed it. As to what might be available domestically in that category I don't have a clue. Till you noted it, I'd never seen or heard of that approach. I'm happy, with the tankless at this point, but should I win the lottery down the road it's something I'd consider in a new location/home.

Title: Re: Tankless Water Heater
Post by: FullRangeMan on 5 Feb 2011, 08:45 pm
Love the idea of the Lorenzetti, but it could be a real mess to retrofit.  In my five year old house (with 200 amp service and all 12 gauge/20 amp circuits) we may have enough circuit capacity, but to run wiring to 13 fixtures would be major.

And I rather like having a (power vented propane) heating source in our finished basement here in the great white north.
Thanks for the English link info. here it is: http://www.lorenzetti.com.br/site_in/portal_duchas.asp

Dear JLM:
This kind of electric shower works fine with a gas shower or even boiler/tank, then retrofit is not mandatory.

And it is a very safe system, no electric shock.  IF the house do not have a electric ground, just use the last part of the water tube in plastic tube (the water tube between the wall and the shower).

For this electric shower I use a 50 amp circuit breaker. Electric showers are perfect for me, I do not see any prob, low price, fast to repair, new models every year if the lady house fells this one are ugly.
Many houses use both systems here, electric and gas, if the gas tank empty, use the electric.
Regards, Gustavo
Title: Re: Tankless Water Heater
Post by: Bizarroterl on 3 Mar 2011, 10:42 pm
We have a Bosch tankless I installed 10+ years ago.

Disadvantages: 
    Takes a little longer for hot water.  The difference is that the tankless requires a little time to heat up its heat exchanger.
    The model we have doesn't have a thermostatically controlled output.  It raises the water temp by an adjustable amount.  Since the incoming water temp changes from summer to winter I have to adjust the output twice a year.

Advantages:
    Less energy (gas) use.
    Unlimited hot water.
    Takes up less room.
    Did I mention unlimited hot water?


  The issues others have mentioned about a tankless not being a good choice in northern climates isn't a problem with tankless heaters.  Tankless heaters are designed to heat up a certain amount of water a certain amount.  If anyone ends up with a tankless that doesn't heat up water properly, the installer goofed and installed the wrong size unit.
  Manufacturers sell these in several different sizes and picking one too large wastes money and too small won't heat water enough.  Installers that aren't familiar with tankless heaters are used to 1 spec - how many gallons?  With a tankless you need to know the temp of the incoming water in winter, how many GPM will be pulled (flow rates of shower heads, sinks, dishwashers, washing machines, etc that are run at once), and how hot the outgoing water temp is desired.  Knowing that they then have to translate that into BTU capacity and select the correct system.  No wonder there have been a lot of unhappy users.   :cry:


  On my project list is to add solar HW collectors/tank to preheat our incoming water and maybe replacement of the Bosch with a Navien condensing tankless heater.   :P
Title: Re: Tankless Water Heater
Post by: TooManyToys on 29 May 2011, 03:04 pm
Just read through this thread and I'm not trying to be a smartass here, but ..... I guess you didn't get it inspected either.

It appears you have a ground wire attached to one or both plastic water pipes.  That won't work.  All grounding has to be on a metallic pipe that is continuous to earth for conductivity, or wired to the exterior grounding rod by the electrical meter.


If you don't want to be inconvenienced, a tankless is probably not for you. 

My tankless cost me about $600 a few years ago, and I did the installation -- I am no plumber

I hung it on the wall (~20 lbs.?), extended the gas line that was in place for the heater it replaced (screw fittings), added a few feet of copper pipe to connect with the existing inflow and outflow pipes, and enlarged the roof vent from 4" to 6" to handle the larger pipe (double walled spec'd). 

The unit I have requires no electricity at all; it has a wee turbine that creates the spark to fire the burners. 

Seems that electric units make the most sense only when located at the point of use, say under a sink, where you only need small amounts of hot water.  To run a whole house unit, we want fire and want it now. 

(http://www.audiocircle.com/image.php?id=42373)

Title: Re: Tankless Water Heater
Post by: Peter J on 29 May 2011, 03:33 pm
Just read through this thread and I'm not trying to be a smartass here, but ..... I guess you didn't get it inspected either.

It appears you have a ground wire attached to one or both plastic water pipes.  That won't work.  All grounding has to be on a metallic pipe that is continuous to earth for conductivity, or wired to the exterior grounding rod by the electrical meter.

I think you're looking at copper that's painted white. It may indeed provide a ground path. While commonplace many years ago, grounding to water pipes is no longer allowed by most codes, primarily because of the possibility that the pipe could be compromised somehow. On the other hand, if one is certain of the pipe's integrity and connection to earth, it can be viable.
Title: Re: Tankless Water Heater
Post by: Steidl Guitars on 29 May 2011, 06:07 pm
Peter is correct, that's copper that's been painted.  The ground wire was stuck there by an electrician when he changed the main panel on my house, and has nothing to do with the water heater itself.

That said, thanks for bringing it up just in case. 
Title: Re: Tankless Water Heater
Post by: ctviggen on 29 May 2011, 06:44 pm
That grounding may be to ground the two copper pipes together, not to provide a house ground.  I've done the exact same thing for my soft water system (that is, used a copper wire to ground the two copper pipes entering and leaving the soft water system otherwise, the copper piping after the soft water system wouldn't be grounded).  And my house ground is at the meter entrance and directly into the ground.

The NEC still (at least as of 2005, though I haven't checked the 2008 codes) still  allowed grounding to piping entering the home.  There were certain conditions on it, though, to avoid loss of ground.
Title: Re: Tankless Water Heater
Post by: Steidl Guitars on 29 May 2011, 07:08 pm
That grounding may be to ground the two copper pipes together, not to provide a house ground.

That is correct; the ground wire in the photo is about 10" long and is only connected to those two pipes. 

Question.  Is that intended to increase the amount of surface area available to dissipate a ground fault of some type? 
Title: Re: Tankless Water Heater
Post by: TerryO on 29 May 2011, 08:38 pm
I don't know if this will change anyone's mind, but I've served as a County Water Commissioner for over 19 years and the studies that we've seen indicate that the majority of water usage, that the customer gets billed for, is related to letting the water run until it gets hot. Some of the smaller units can be installed under a kitchen counter and will give nearly instant hot water. It can be cost effective, depending on how much your local rates are.

FWIW, a couple of my fellow Commisioners have recently installed them.

Best Regards,
Terry Olson
Title: Re: Tankless Water Heater
Post by: Peter J on 30 May 2011, 02:08 am
That grounding may be to ground the two copper pipes together, not to provide a house ground.  I've done the exact same thing for my soft water system (that is, used a copper wire to ground the two copper pipes entering and leaving the soft water system otherwise, the copper piping after the soft water system wouldn't be grounded).  And my house ground is at the meter entrance and directly into the ground.

The NEC still (at least as of 2005, though I haven't checked the 2008 codes) still  allowed grounding to piping entering the home.  There were certain conditions on it, though, to avoid loss of ground.

Way off topic, but can you elaborate on this for me? I'm not understanding why your plumbing needs to be grounded at all if the ground stake is providing ground to panel and subesequently the house. It seems to me that at the least it would be  redundant, and possibly be a hazard.
Title: Re: Tankless Water Heater
Post by: TooManyToys on 30 May 2011, 04:45 pm
Sorry guys - just being cautious, not a PITA.  It just looked like PVC and warning flags went up as I've seen homeowners do that before.

I think you're looking at copper that's painted white. It may indeed provide a ground path. While commonplace many years ago, grounding to water pipes is no longer allowed by most codes, primarily because of the possibility that the pipe could be compromised somehow. On the other hand, if one is certain of the pipe's integrity and connection to earth, it can be viable.

Peter is correct, that's copper that's been painted.  The ground wire was stuck there by an electrician when he changed the main panel on my house, and has nothing to do with the water heater itself.

That said, thanks for bringing it up just in case. 
Title: Re: Tankless Water Heater
Post by: srb on 30 May 2011, 05:05 pm
Sorry guys - just being cautious, not a PITA.  It just looked like PVC and warning flags went up as I've seen homeowners do that before.

That's what I though at first too, but once it was revealed that it was painted copper, I realized that the elbows didn't have the wall thickness of PVC.
 
Steve