My Tankless Experiment

[jadnashua]

One of the complaints is how much the water tempurature can change with changes in the volume. Sometimes you only want a trickle of hot - it can become very hot. This may be a significant difference from medium or full-flow temps. This is why they sometimes specify a tempering valve.

Do the installation instructions specify a flow restrictor, or is it built-in?

Also note the time it takes to fill the tub with the restrictor in there. A thermostatically controlled tub/shower valve might be a very helpful addition for both safety and comfort.

[talkingdog]

JADP, but on the Japanese market, where tankless once ruled, everybody is switching over to heat pumps with 300 liter tanks so that they can take advantage of cheap off-peak electricity. The late night electricity costs about 1/6 of the daytime rate. These units start at about $2000.

People with RFH or otherwise heavy demand for hot water will install one of Honda's gas-powered Micro CHP units, which at current gas rates is competitive with a heat pump and will provide nearly as much heat on demand as a tankless. These are about twice the price of heat pumps. The Micro CHP has a generator built into it that runs off the waste heat that would normally be lost, and the advantage of this is that you get to sell the juice you generate to the power company at peak-rate charges, retail, and this is a big advantage if you are running the RFH flat out during the day.

[statjunk]

Mark,

Would you consider buying a second home close buy to make the test more fair?

You might also want to sponsor a family to live in the house. It would be pretty tough to take twice as many showers and wash twice as many dishes.

Just a thought! LOL.

Tom

P.S. I'm interested in the outcome of the test keep it going.

[patrick88]

just installed a Rinnai tankless the other day don't know the spec's but we only charged $2,600 for the install. It was a propane and the home owners had an old power vented propane tank heater. It went very well and I have been told by my bosses we have installed about 7 total.

It is very easy to say this product is no good or another is better because of one reason or another. Every part of the country has many different reasons why one product is better or worse. I have great water at my house (well water) but friends on the other side of town have sucky water. If a tankless water heater is no good because of hard water well how are the other fixtures doing with the hard water. I have seen some great fixtures destroyed from hard water and the home owners will not or can not install proper filters, or softeners. What works in one part of town or country may not work in another. That is why knowing all the facts as a pro is the most important part of being a plumber.

I used to install symmons tub/shower valves when i lived in Essex county Mass. but out in Hampden county they get destroyed from the iron in the water. Does this make symmons valves crap? No it just says i needed to find something that works here.

Now if every plumber in every county in every state did the same test as Master Plumber Mark then we might have a good idea of what works best in your city or town.

Just wanted to give my $.02.

Great thread.

[master plumber mark]

honestly ,, it really does not matter where you
put one in... the btu cost can be factored in within
a pretty close range....

I am testing for cost and efficinecy differences with my trusty gas meter...

then I am gonna try to figure out how many years it will take before that 2600 invenstmet will pay off.......

I have Delta 1500 pressure balanced valves in the home
and the high maintaince wife.....

and other little factors like ease of operatioin
ect, ect... how long it takes to get hot water
60 feet away....


Of course this state is ground zero for nasty water,
but My CLACK water conditioner should make
the water at alomst 0 hardness....

and dont forget the cold water in the winter time....
about 48 degrees and lower.....


If it can work here without too much in-convienance,
and it acutally saves money and you have an eventual payback.....

then its good about anywhere.....

[master plumber mark]

Submitted for your viewing approval ....and consideration....

one over-weight plumber with nothing else better to do today
while being stuck baby- sitting two 6 year old girls untill 7 pm tonight

on a beautiful Sunday morning in indianapois indiana....

one new gas meter bought off e-b// for 89.00.

the meter is pre-tested and pre-set at 6.2 btus ....

One 2 year old 75 gallon gas Bradford White heater already hot
and the unit is covered by a blanket.......


now how many cubic feet of gas will it take to heat the water
for one week to two months.....????

inquireing minds want to know... sept 16,, 2007

(I dont get out very much....)


Now after about 4 months....I plan to switch to a tankless water
heater Probably a TAKAGI or Rheem just to see how it performs in
basically the same conditions.......

started experiment with 6.6 btu at high noon.



I am curious as to how much this thing will spin in an hour.....

how much the piolit light actually uses per day

as you can see it goes by 10ths of a btu......

probably wont come on today to re-heat till tonight.......

[Bob NH]

Mark,
You need to figure out what that calibration is, and compare it with your regular gas meter. 6.2 and 6.6 BTUs on the meter are not correct.

It is probably calibrated in Cubic feet, or maybe 1000's of cubic feet. One cubic foot is about 1000 BTUs.

Your gas company probably bills you in Therms. One Therm is 100,000 BTUs, which is about 100 cubic feet. One Therm may cost $1.50 to $2.00.

[master plumber mark]

Bob...thank you for the informaion

I will find out more about the meter from the
person I bought it from...

and I will get out my gas bill, or call the gas compnay

when it came out of the box it was factory tested
and run through its paces to 6.2


So after I installed it and blew out the meter itself and
fired up the gas heater it moved to 6.6


it is now at about 7.6

I wonder how much that piolit light
actually cost me over the last 3 hours....???


any advice on how to calculate it is appreciated...

just because I can rig up a gas meter dont mean
I know what the hell I am talking about...lol


Brand New Warehouse Stock. Note:
All meters show 4-8 cu ft of useage right out of the box.
This is from the factory calibration run performed just prior to packaging at the factory.

[Bob NH]

Brand New Warehouse Stock. Note:
All meters show 4-8 cu ft of useage right out of the box.
This is from the factory calibration run performed just prior to packaging at the factory.

EDIT: I just looked closely at the picture and it says that it is rated in Cubic Ft.

From the quoted statement, if that is from where you got it, then I suspect that the 6.2 was cubic ft. Since there are about 100 cubic ft in a Therm, and the price of one Therm is about $2.00, each cubic ft of gas (as from 6.2 to 7.2 on the meter, would be about $0.02.

If you have a 30,000 BTU per hour water heater, then I suspect that it will use about 1 cubic ft in 2 minutes when it is firing. You could check that by running enough hot water to get it firing for a short time.

[master plumber mark]

I dont know if this is ok.....but here it is.....

I am waiting for the fellow to reply to my questions..

you should be able to look up the meter through this link.

http://myworld.****.com/hopefulwon/

http://cgi.****.com/ws/****ISAPI.dll...MEWA:IT&ih=006

[GrumpyPlumber]

Mark, geesh...lets simplify this!!!!

Make sure NOTHING else in the house is running on the gas, check your houses gas meter reading and write it down, then check the tankless's.
Start the tankless and run it for a few.
Check both meters, subtract the reading you get on your main and cross referrence to the tankless meter.
Your houses meter will read CF (cubic feet), do some simple math if the two readings don't jive.

[GrumpyPlumber]

"Meet Mr. MasterPlumberMark....
Ordinary disgruntled plumber by day....Super-cyber Plumber by night.
He's about to embark on a mission, not some ordinary mission, but one of utmost importance that even he doesn't know what will bring him to...
He's about to embark on a mission in ....THE TWILIGHT ZONE!"

[Dunbar Plumbing]

This might end up on Montel.......better yet, Oprah.

MPM is goin

[GrumpyPlumber]

This might end up on Montel.......better yet, Oprah.

MPM is goin

Springer?
Could we aspire?

[master plumber mark]

Grumpy, read the posts closer....

I dont think I can make it any simpler...
now its all just figuring the math on the btus



Yes....I had a lot of time on my hands today...

baby sitting 2 ..6 year old girls...
that was pretty dull , but I took them for a walk to
the local store down a few blocks for candy ...your basic parenting

from 12 till 6 with not much else to do....


did a little boookwork, faxed some bills ect.....



anyway.....the meter is in the pic.... you can see
at what point it started reading my gas to only
the 75 gallon 75,000btu brad white heater....
at 6.6



you can see my laundry room..the water heater and
how I installed the meter on the floor

and nothing else is on that 3/4 line

with only the piolit light going it went from 6.6
to 8.4 at from 12 to 6 this evening.....


I am trying to keep this simple and it seems fairley easy

so once I figure out the math its no big deal to
know what a 75 gal heater average costs are per month.

bob newhart seems to have a handle on that already for me.