# Here's another one



## JamesNLA (Jun 2, 2006)

Tankless Hot Water Heater Installation last week. 

About 10 hrs by myself (helper is on vacation).....(again).

That tanked heater was dated 1980. He holds my record of tanked still working at 27 years. It was pissing at the bottom and I had to fight it a little to clear out the sand to get it to drain.

Tankless is a Noritz 7.51M-O.D.
Takes 199,999 BTU.

This unit is BY FAR the quietest tankless on the market. I don't wanna get into all the details as it's Sunday Morning, and I don't feel so hot at the moment. Maybe around half time of the Colts game I'll yap a little more, maybe not!!

This house belongs to an EC, and when I was looking over the job, I just assumed he was going to do electrical. His responce was....."Son, you couldn't pay me enough enough to go under and string a line."

I had a laugh, till I went under on the start day. No dead animals, just BAD MESSY remod work. all sorts of screws, nails, debris ALL OVER the crawl.
O well, it's part of the job, when one doesn't have a helper.....again.....

This unit, I wanted to to a relocate to outside.....the vent pieces cost more than tripple the materials needed to relocate to the outside. And the new location is right near the kitchen so it makes sense to do.

Fun Fun.


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## kbsparky (Oct 14, 2007)

I suppose in SoCal you don't have any concerns about freezing pipes like we do here in the Mid-Atlantic area. 

Such an installation would require an insulated enclosure to ensure the pipes didn't freeze..... :whistling


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## JamesNLA (Jun 2, 2006)

I've been on jobs in Northern California. I would NEVER dream of doing an install like this in places where it freezes. That said, the unit is designed for that kind of install. Internal heating elements keeps it from freezing up. The plumbing is a different story. I could have wrapped the cold side, but it is not a concern here. Actually this area is sunny most days, we don't get much rain. Al Gore stole all the rain!!


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## KillerToiletSpider (May 27, 2007)

JamesNLA said:


> I've been on jobs in Northern California. I would NEVER dream of doing an install like this in places where it freezes. That said, the unit is designed for that kind of install. Internal heating elements keeps it from freezing up. The plumbing is a different story. I could have wrapped the cold side, but it is not a concern here. Actually this area is sunny most days, we don't get much rain. Al Gore stole all the rain!!


The hot water always freezes before the cold does.


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## smellslike$tome (Jan 22, 2006)

KillerToiletSpi said:


> The hot water always freezes before the cold does.


I've got to hear the thermodynamic explanation for this. Please, do enlighten us.


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## KillerToiletSpider (May 27, 2007)

smellslike$tome said:


> I've got to hear the thermodynamic explanation for this. Please, do enlighten us.


Wish I could, I know it from six years of doing service work, hauling around thawing machines for two months out of every year, the water was always froze on the hot side and not the cold.


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## randomkiller (Sep 22, 2007)

smellslike$tome said:


> I've got to hear the thermodynamic explanation for this. Please, do enlighten us.


 
I have seen it that way myself for years with no reason as to why but I also saw on mythbusters that it is just a myth.


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## JamesNLA (Jun 2, 2006)

It is true that hot water CAN super cool faster than cold water. If you guys seriously want to hash out Neutons Law of cooling, be my guest.

For the sake of my poor thread, hot water CAN freeze faster than cold water.


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## Herk (Aug 1, 2007)

I've heard explanations from all sorts of people, including chemists, as to why hot water does or doesn't freeze quicker than cold. In my opinion, based upon observation and experience, it does freeze faster. But there doesn't seem to be any certain agreement on the subject. I have tested hot and cold water on the porch in bowls, and the hot seemed to be freezing faster. It seems like a frozen pipe is hot rather than cold a high percentage of the time.


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## KillerToiletSpider (May 27, 2007)

I forgot, nice work on the installation James.


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## Putty Truck (Oct 6, 2007)

JamesNLA said:


> Tankless Hot Water Heater Installation last week.
> 
> About 10 hrs by myself (helper is on vacation).....(again).
> 
> ...


There seems to be a leak or are those tears? Nice job.

So...tell us how much you charged and how much everything costs...


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## JamesNLA (Jun 2, 2006)

Thanks!

No leaks - I was flushing out the inlet filter, showing client how to relieve pressure for either hot or cold for the Iso valves.

Cost??

U tell me.

You see the meter in the backround, how much time spent on the job. The relocate was about 40 L.F.

Relocate was done in Pex
Electrical....aside from what you see, minimal.


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## Putty Truck (Oct 6, 2007)

JamesNLA said:


> Thanks!
> 
> No leaks - I was flushing out the inlet filter, showing client how to relieve pressure for either hot or cold for the Iso valves.
> 
> ...


$3,700.00, inclusive. No permit.


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## KillerToiletSpider (May 27, 2007)

JamesNLA said:


> Thanks!
> 
> No leaks - I was flushing out the inlet filter, showing client how to relieve pressure for either hot or cold for the Iso valves.
> 
> ...


$4500.00, piped in copper, no electric.


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## a2zhandi (Nov 2, 2007)

In a sense heated water looses some impurities. (Distilled) . Water consisting of only hydrogen and oxygen will freeze faster. Impure water holds greater mass. Which in turn takes longer to freeze


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## a2zhandi (Nov 2, 2007)

Further note:
Supercooling may be important to the effect. Supercooling occurs when water freezes not at 0° C, but at some lower temperature. This happens because the statement that "water freezes at 0° C" is a statement about the lowest energy state of the water -- at less than 0° C, the water molecules "want" to be arranged as an ice crystal. This means that they will stop zooming around randomly as a liquid, and instead form a solid ice lattice. However, they don't know how to form themselves as an ice lattice, but need some little irregularity or nucleation site to tell them how to rearrange themselves. Sometimes, when water is cooled below 0° C, the water will not see a nucleation site for some time, and then water will cool below 0° C without freezing. This happens quite often. One experiment found that the initially hot water would supercool only a little (say to about -2° C), while the initially cold water would supercool more (to around -8° C) [12]. If true, this could explain the Mpemba effect because the initially cold water would need to "do more work" -- that is, get colder -- in order to freeze.


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## thom (Nov 3, 2006)

As to dragging a line through a crawl space, I was once working in the mountains, had to do just that in a crawl that I would not fit in. The owners kid was out playing with his RC truck (big wheels). I had him drag a string through the crawl then I used the string to pull the line (No, I didn't staple it up, no way to fit in there to do it). The kid and his dad were so excited that he could actually do something productive with that toy.

The plug appears to be 110V probably 20A circuit. How much Hot Water does that supply? Enough for a good shower? A shower when the washing machine is running? Two showers?


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## JamesNLA (Jun 2, 2006)

> The plug appears to be 110V probably 20A circuit. How much Hot Water does that supply? Enough for a good shower? A shower when the washing machine is running? Two showers?


This is a Nat Gas unit. I believe power consumption is 64 Watts.

As for the amount of showers.....
The way it works is, the temp rise chart will determin the amount of GPM. My area, I have a 60 degree rise. Temp comming into the unit is 60 degrees, I want to heat water to 120, therefore we have a 60 degree rise. This rise is a give and take, meaning more temp rise, less GPM -- lower temp rise - more GPM.

This particular install is a 7.51 GPM unit. So in the best situation this thing can max out at 9.8 GPM. That is with only a 30 degree rise, can't do much with that, unless we have solar involved. Than things change a little. For my 60 degree rise, my MAX best is 5.6 GPM. So think of an average fixture, the areator is about 2.2 GPM, take your shower head ratings into consideration. This is how I properly size the house.....not the occupents. Average shower is a 80-20 to 90-10 percent hot - cold mix. So let's say two, 3 gpm shower head going. that's 6 GPM, minus the ratio. I guestimate it at 5.6 to 5.8 GPM.

As you can see, we are maxed out with our 7.51 unit.
So now I need to consider the rest of the house. Assuming this is not an illegal alien home (where 40 will live in a 2 bedroom structure) I am looking how many 1.2 baths...kitchen layout - multiple laundry rooms on larger homes....etc... One has to understand, if we sized these things to run every hot water fixture at the same time, no one would buy them. Who wants to spend 2-6 grand just in unit(s). So im most situations 2 bath average 1800 sf. home gets this 7.51.

I have another one comming up where it just under 1900 sf, but the home setup requires the next size up.

The homes existing plumbing also needs to be considered. Only so much water can flow in a 3/4" pipe. 

Hope that helps


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## thom (Nov 3, 2006)

So, what's the electric power do?

I have two tankless units. One heats my spa, the other is the back-up for my solar heating system. Neither uses electric power. The flow of water through the unit turns the gas on and off. Both have standing pilots.


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## JumboJack (Aug 14, 2007)

thom said:


> So, what's the electric power do?
> 
> I have two tankless units. One heats my spa, the other is the back-up for my solar heating system. Neither uses electric power. The flow of water through the unit turns the gas on and off. Both have standing pilots.


It powers the pilot and the electronics ie: thermostat


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