My Tankless Experiment

[master plumber mark]

that plumb biz news letter is usually pretty dry.....
but its a good read one in a while....I glance it over

you are sort of close to about right with that estimate but....

the 23 a month was supposed to be the 50% high end of
saveings the absolute most you could save useing the tankless salesmens numbers.


of course the tankless folks are going to use the absolute highest % for saveings
and they are going to use the absloute rock bottom numbers for installation costs too
to get the years down on the pay back end ..... and that is all smoke and mirrors to me....

but the Plumb biz guy also wants you to factor in
some sort of ball park estimate for enlargeing the chimmney---and enlargeing the gas line too....

into the overall cost and then figure out the payback from there..

it will be interesting to see the numbers he gets back....


they are not factoring in future maintaince to this equation to me
its really a FUZZIE shot in the dark...

[GrumpyPlumber]

The $3K ballpark figure is for install with a 3/4" upgrade on the gas supply, as well as the vent set-up.
They're wall mounted, so you generally set them up on the foundation wall as close to where they'll vent outside as possible because the SS vent is expensive (around $80 for a 4' length of 4" if memory serves).

Maintanence is another issue, but from what I hear it isn't much more than a yearly vinegar flush, which you're "supposed" to do on tank types anyway.
Tankless have been around for many years, much like cell phones, they were originally a high end item that was too cost prohibitive for the average Joe.

[master plumber mark]

week #8 have used 5680 cu ft so far..


I might have a Rheem tankless with a scratch
and dent on it in a few weeks.....

[markotah]

Fact: One product is not good for all applications!
Tankless electric is only a good choice for point of use small sink applications especially in colder climates. Gas on the other hand is not new and has been in Europe for over 40+ years. (far longer than tank type pv units). In the northeast a tankless unit can cost 1/2 as much to operate. Comparing to a 75 gal 70K tank type heater you only have 70% of usable water. Call it 53 gals and a recovery of about 70 gals per hr. Total 123 gals. Take a Rheem 199,000 BTU unit (and all manufacturers are equal on the same BTU) 40* incoming water and 117* supply temp and you will have 4.3 gpm continiously or 258 gals per hr. You need to calculate the peak flow but if you fill the whirlpool someone can jump right into a shower and still have h/w. If you need a higher fill rate you can twin units together for higher demands. I have 2500 sq ft homes in a subdivision in CT and no complaints with a single units. I have larger homes where we have twinned units and the end users are happy. The key thing is to know what you will receive for flow with the coldest incoming water. READ LITERATURE CAREFULLY! Most of the 7.4 or 6.9 gpm you see are @ 45* rise. ALSO be aware of larger units over 200K. Most states require an ASME rating on units over 120 gal or 200K. This can be an issue with both the inspectors but more importantly your insurance carriers.
Last the warrantys on most tankless units are better than the standard tank warranties.

[markotah]

The $3K ballpark figure is for install with a 3/4" upgrade on the gas supply, as well as the vent set-up.
They're wall mounted, so you generally set them up on the foundation wall as close to where they'll vent outside as possible because the SS vent is expensive (around $80 for a 4' length of 4" if memory serves).

Maintanence is another issue, but from what I hear it isn't much more than a yearly vinegar flush, which you're "supposed" to do on tank types anyway.
Tankless have been around for many years, much like cell phones, they were originally a high end item that was too cost prohibitive for the average Joe.

You need to qualify the install. If your customer has a chimney and is not runnining out of h/w payback may not be there. But if you have a new installation and are considering a PV or DV tank type unit the tankless is that much difference in price assuming you can mount on an outside wall. The DV units take all combustion air from outside which is better. The Nat Gas Code states you need 50 cu ft of area for every 1000 BTU. A 60'x20'x8' room only has 9600 cu ft and you would need 10,000 cu ft for 200,000 BTU.

[jadnashua]

Where I live, in the winter, the incoming water can be 33 degrees. a 45-degree rise isn't even warm! I'm surprised you can get by with that in CT. If you have a boiler, I still think an indirect is the way to go.

[master plumber mark]

I am wondering how cold the water will be around jan 15th in INDY...

My guess is it will be down around 35 degrees too.....

Thats cold water....and I honestly dont think one of the
tankless can even hope to deliver the same heat that
my 75 gallon can......

right now the out going hot water temp is set at.....130 deg

the cold incomming is 60 deg....

I am useing about 650 cu feet a week at 60 degrees

wondering how much more cu feet it will take to
keep up when the water crashes ...


Sittingat home today with a kid witht he flu today
thnk I will call teh gas company today and
get info on the cost per therm

[Waterloo]

Had a flex water heater pipe leak on me today. I tightened it up too much and split the gasket. Of course, I only put the water heater in yesterday. At least my sweat connections have held...

When I moved into my home, the previous owner (who had the house built) had installed two electric tankless water heaters (SETS) - one 22KW and the other 11KW. I could heat up 3 gallons a minute by 75 degrees. Or, more likely, 4.5 gallons per minute by 50 degrees. We didn't need that much water heated, so the second one (11kw) got turned off.

However, the darn thing took time to modulate to find it's set point, and since it always comes on "full blast" then modulates down, it ends up tripping it's resets. So, every week or two you end up downstairs resetting them.

It's not too bad for just yourself. You get to know how the thing works, and how you have to run the shower for a bit to let it equalize. But when relatives show up and try to take showers, they end up fighting it constantly. It gets too hot, so they reduce the amount of hot water. Then it gets too cold, so they increase the amount of hot water. Of course, it's 30 seconds to get to their shower from the tankless, and the tankless can take 15-30 seconds to find it's setpoint. It also can be challenging for a dishwasher.

This brings me back to why I hate plumbing. I kept the tankless SETS heater. The output of it now goes into a standard electric water heater. I now get a constant temperature out of the faucet. And, by having the tankless in front of it, I doubt anyone at my house will ever have a cold shower.

Overall, I love the concept of the tankless design. But the temperature fluctuations drove me (and everyone else) nuts. I'm sure gas ones are different (I read that they reduce output flow to maintain temperature), but the electrics really need to be considered pre-heaters.

[master plumber mark]

I would put up with that kind of trouble or
about one week.....

those electric tankless would be out in the trash...

It sounds like you threw out a couple of
tankless water heaters over the weekend

[Waterloo]

Nah - they're too expensive to throw out. It just feeds into the tank now. I don't ever have to worry about running out of hot water. I could take a 4 hour shower if I wanted to....

[Raucina]

E B A Y
If people want to advertise their products here, they will need to talk to me and pay for that advertising.
I don't offer free advertising. [Terry wrote]
__________________

Over on the well and pump forum we have a guy that has relentlessly advertised his product for at least a year, and another that posts links to his sales site. I can tell you that more than a few people are bothered by it. Are those commercial sales persons exempt from that rule for some reason or do they pay for the privilige? They say that they do not. Are there different rules for each forum?

I know its Terry's football and he can throw it where he wants, but I think we patrons of this media have a right to see the advertising on the side of the page and not in the content disguised as help.

[master plumber mark]

did you post to the wrong thread??

[Mikey]

I kept the tankless SETS heater. The output of it now goes into a standard electric water heater. I now get a constant temperature out of the faucet. And, by having the tankless in front of it, I doubt anyone at my house will ever have a cold shower.

Wouldn't it be cheaper to use the tankless as a post-heater, rather than a pre-heater? As a pre-heater, the tankless will run whenever the flow demands it, even if the demand is only a few gallons. As a post-heater, it would only run when the tank-type heater's supply of hot water has been exhausted.

[jadnashua]

The tankless I've looked at (and that's not many) use a flow switch to turn on...they don't necessarily care if it is hot water. If it is, they may modulate, but they still turn on. Then, you could get REALLY hot water, and could have steam pressure problems. I'd restrict it to the input side, if you were going to put them in series. Now, some of the more sophisticated ones are designed for that, but they have interconnected controls which wouldn't be available when connected to some other heater.

[Mikey]

Good point, Jim. Any idea where I could buy one of those flow sensors? It might be a good way to control the chlorinator in my water system.