# tankless application....?????.



## Master Mark (Aug 14, 2009)

I went to a chevy delaership last friday to look at
a mess they had back in the bays where they use a 
hand sprayer to wash down cars that they pull in.....

they had a 50 gallon Smith power vent sitting about 12 feet in the air on a platform about 10 feet away from where all 
this spraying and car washing is going on... it turns out that the water and mist is being sucked into this heater and has totally rusted out the chimmney and burnt out the blower motor... in only two years.......

I have bid the job with a 75 gallon Bradford white.. moving the heater 6 feet further down the way and lower to the ground on the other side of a block wall ...and lowering the 
whole thing to about 8 feet off the ground.... building a platform and installing a water softener under the heater.

I have found out that others are bidding this with a Tankless heater installed on the wall with a Freje unit to soften the water....

my question is...... A tankless sounds tempting, but dont you have to have a continous flow of water through the unit to get that burner to kick on , something about a flow sensor 

 if someone is just inermittingly spraying off a car then stopping the flow of water ....... 

wont that be a problem to get hot water for short blasts????


I am being asked why a tankless wont work properly
and for a price on a tankless.........


any info would be appreciated.......


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## RealLivePlumber (Jun 22, 2008)

As much as I don't like tankless, that might be somehing to consider in this application. 

I would be concerned about the flow rate of the hose, if it's like 5 gal/minute, you have to take that into consideration. Also, check the gas supply, (and meter size) might have to increase it. 

I would build the price of a second unit into the job, so you have parts to swap out in case of a problem. :laughing:

Stick with Noritz.


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## ZL700 (Dec 8, 2009)

Perfect since I doubt they use water much over 80 to 90 degrees.


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## Master Mark (Aug 14, 2009)

*gas service*

gas service is 1 inch no big deal

the vent is just out the other side of the block wall

its the constant on and off washing cars , it seems like it
would not work properly. They are useing someting like a 
pressure washer hose with a spring loaded sprayer handle.

unless they hold the hose constantly on, isnt this going to affect 
the burner and flow??

.


it makes me wonder how well they would work with the new 
high end washing machines that only take short bursts of hot water ????


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## service guy (Jun 26, 2008)

If they only use short bursts of hot water, then you may have some problems. If they use "longer" bursts, then a tankless may be just fine.
When they pull the trigger on the pressure washer, the water will heat up and have to travel down to the pressure wand. If it is very short distance, I don't think it would be a problem, if they have a long distance of line though, you'll need a secondary storage tank and a recirculating pump to keep a constant supply of endless hot water without having to wait.

You could install the tankless, and add in the contract a secondary price "just in case" to put in a small secondary storage tank heater and recirc. line. Ask them if they mostly use it in short bursts, and if so explain that they will be getting 'cold water sandwiches' every time they fire the unit for a few seconds.

If they still insist on tankless, put it in the contract that you warned about the cold water burst when they pull the trigger.


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## Tommy plumber (Feb 19, 2010)

Master Mark said:


> gas service is 1 inch no big deal
> 
> the vent is just out the other side of the block wall
> 
> ...


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## plbgbiz (Aug 27, 2010)

You might want to contact ckoch407. I think he'll have an answer for you that avoids a "large" storage tank.


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## Protech (Sep 22, 2008)

Install a small tempering tank and a circ pump. Use a takagi for your tankless as it is temperature modulated and can heat recirculated hot water. Set the circ pump on a timer so that the thing isn't heating when they aren't open.


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## DownHill (Oct 15, 2010)

Steam Jenny. Done.


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## Protech (Sep 22, 2008)

You can wash a car with steam?!?



DownHill said:


> Steam Jenny. Done.


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## DownHill (Oct 15, 2010)

Protech said:


> You can wash a car with steam?!?


With the burner turned down or off. Combination machine.


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## Master Mark (Aug 14, 2009)

*that sounds like fun..what would teh cost be???*



Protech said:


> Install a small tempering tank and a circ pump. Use a takagi for your tankless as it is temperature modulated and can heat recirculated hot water. Set the circ pump on a timer so that the thing isn't heating when they aren't open.


 
Protech thank you for the tip.... 

 it sounds like a lot of trouble to me.
as I have never tampered with anything similar since 
1983.... way back in my solar days... .

out of curousity, what would be a ballpark price for
one installed in a Takagi???. mid range unit doing 
unlimited hot water use??? 

with EXTREMELY HARD WATER. probably around 26
of course I would install isolator valves to de-scale it

 gas is there in one inch.. and maybe its even 1 1/4
its back to back with the outside block wall... 

might have to by-pass the simmons tempering valve they have hanging on the wall...which only goes to the laundry and to this unit...

so ............what is it worth ???


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

as of this evening , they are leaning towards the 
75 gallon power vent set on 140, going though the
existing simmons mixing valve kicking it down to 115.

 ...to take care of all the car washings and laundry they do....

I might have oversized the softening system with 2 twin 60,000 grain mineral tanks in tandum....but I can guarantee that they will never run out of soft water no matter how many cars they send through the place... 
I got a deal on them anyway:laughing:


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## Protech (Sep 22, 2008)

Bout $2400 without a softener.


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## DownHill (Oct 15, 2010)

Just to keep it interesting. 

http://www.steamjenny.com/gascombo2.html


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## Master Mark (Aug 14, 2009)

*that sounds cheap*

thank you

that actually sounds sort of cheap to me.

is this because of the ease of installation I have described to you????...

that is about the same price as the power vents are getting 
installed around here for every day....

....


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## DownHill (Oct 15, 2010)

And I think you'll have problems with cold water sandwiching with a tankless more so than a tank or some alternative. 

Flow controls turn ons have been decreased in gpm but still there is a difference or lag time to get tempered water as opposed to a tank. Especially with pulsation. Some frontload washer owners experience this.


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## SewerRatz (Apr 25, 2009)

I would price it with a direct vent tankless like a Rinnai R96 or the Noritz 841-DV Otherwise I would put in a power vent direct vent unit so it would get its combustion air from the outside. It will not be sucking up he water mist. 

The last Rinnai I installed I got $3600 with out a softener.


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## Master Mark (Aug 14, 2009)

*direct vent*



SewerRatz said:


> I would price it with a direct vent tankless like a Rinnai R96 or the Noritz 841-DV Otherwise I would put in a power vent direct vent unit so it would get its combustion air from the outside. It will not be sucking up he water mist.
> 
> The last Rinnai I installed I got $3600 with out a softener.


That is a good idea Swere ratz..
a power vent direct vent sounds like a good alternative..
we dont use or see many of them in these here parts....

I will have to look into that one...in a Bradford White
they have to be available, but I have never, ever run into one
I am sure they are available , maybe special order....who knows??

3600 for a Rinnia sounds more like the price I was thinking for a tankless.
not including all the pumps and whistles needed to make it work right..


now this makes me wonder how much mist and moisture 
can a tankless handle before it shows signs of corrosion in a situation like this one???


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## DownHill (Oct 15, 2010)

Why a power vent? Can you not get a direct vent installed? 

I'd rather have a direct if possible.


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## Master Mark (Aug 14, 2009)

*I agree*



DownHill said:


> Why a power vent? Can you not get a direct vent installed?
> 
> I'd rather have a direct if possible.


 

its a good idea, I just have not seen one ever around here
which I think is odd.... maybe its a conspiracy to keep
hoosiers in the dark ages ????

this would be the perfect application for a simple water heater 
without all the controls and fans to go wrong with it in this wet crappy garage..



I found a good link to one ...pretty expensive on line anyway.

gonna call on it tomorrow......

http://www.pexsupply.com/Bradford-W...Energy-Saver-Residential-Water-Heater-Nat-Gas


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## Protech (Sep 22, 2008)

I rarely do tankless, so my shot from the hip may be low.......


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## Tankless (Jun 12, 2008)

Wrong. Ken, I would expect a more thought out answer from you. Your system just destroyed the warranty and limited the life of the unit to less than 5 years......keep thinking, you can do better.




Protech said:


> Install a small tempering tank and a circ pump. Use a takagi for your tankless as it is temperature modulated and can heat recirculated hot water. Set the circ pump on a timer so that the thing isn't heating when they aren't open.


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## Protech (Sep 22, 2008)

I'm not in a thinking mood tonight. You should just spill the beans. Everyone knows who's the tankless master on here so let's just skip the tease eh? What's wrong with that setup?



Tankless said:


> Wrong. Ken, I would expect a more thought out answer from you. Your system just destroyed the warranty and limited the life of the unit to less than 5 years......keep thinking, you can do better.


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## Master Mark (Aug 14, 2009)

*well what is the answer*



Tankless said:


> Wrong. Ken, I would expect a more thought out answer from you. Your system just destroyed the warranty and limited the life of the unit to less than 5 years......keep thinking, you can do better.


Please chime in here and tell me what would work in a situation like this one


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## Protech (Sep 22, 2008)

Perhaps he thinks I was not recommending a softener? That's the only thing I can think of......


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## Tankless (Jun 12, 2008)

This is not the best situation for a tankless system but it would work. Mark...understand something, right now is the hardest part of the job, the design. Any moron monkey can pipe it and make up all the other parts but the design is where you earn your money. A tankless does not like mist....of any kind. Pay attention to your CLEAN air make up...not your moist clean air make up. Tank or tankless you need to solve that issue, period.

The way I explain it to folks is we are not changing the manor in which we deliver the hot water, just how we heat it. The off and on will cause un-needed wear and tear....there are a few ways to combat this however it will get pricey very quickly.....hard water (which will be softened - so hard water is no longer an issue) will be addressed.....so next you have the dreaded horrid awefull fear of God Cold Water Sandwich.......










There, there's the answer to your prayers. Factor in another 100 bucks plus fittings and the hassle to charge it up correctly (I do them minus 2 psi of static).

What's next?.......

..............This is just one way to do it. No pumps for something like this unless there is a recirc line. If there is, now you will really earn it. I designed my own recirc system for tankless systems that I sell as an alternative to the push button Metland system. People who have 5 million dollar houses do not want to push buttons to get hot water. I am not interested in announcing my design to the free world. I did a lot of testing to come up with what I have and will keep it that way. However that said, there is an easier way to do all this. I hate to admit it but this situation may just warrant the dreaded N word. No, not that word, I'm not a racist. The Navien NR 240A is what you want to know about. It's a max load of 200kbtu, built in buffer tank that allowed point of use without always firing up ther burners. This unit also has a built in Armstrong pump (my favorite maker of pumps...hint...hint). PVC venting and DV ready. This is what is called turn key design. The South Koreans did all the work, you just have to install it. Do it by the book because you want that warranty. Find out about commercial applications....I do believe they make a commercial line, that's basically the same thing....it just costs more (shocker).

I have had better luck with the NR series versus the older CR. The CR is obsolete (thank Gawd).

Keep mist OUT of the gas combustion chamber and the water soft and this design will last many years.....barring the Navien takes a self imposed shyit.

The design is the hard part Mark but with some thought and research it's very do-able. The price point with the Navien will most likely help beat your compeditors unless they too are bidding this same design. Good Luck!!


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## Tankless (Jun 12, 2008)

Protech said:


> Perhaps he thinks I was not recommending a softener? That's the only thing I can think of......


 
That's the only reason I gave you 5 years....was because it had a softener on it! I give you credit....you won't catch me yapping about solar designs.....notta chance pal!


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## Protech (Sep 22, 2008)

So your saying that it will not last due to the recirculation into the tempering tank?


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## Tankless (Jun 12, 2008)

Protech said:


> So your saying that it will not last due to the recirculation into the tempering tank?


I'm saying it will not last because of the recirculation in general. Continous flow (whether burning or not) will cause the internal failures at various parts of the system.....basically the weak link will be found. Bypass and flow sensor(s) are usually tops on that list however hard water expands on that theory ten fold.


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## Tankless (Jun 12, 2008)

Cold Water sandwich solution: http://www.hvacquick.com/products/r...anks/Metlund-Hot-Shot-Thermal-Expansion-Tanks


your welcome.


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## Master Mark (Aug 14, 2009)

*misty and cold*

Tankless..

from what I am hearing, the mist will screw up a tankless about as fast as the power vent... 



at this time I am going to look for the direct vent heater
75 gallon from Bradford white ,,, and simply get the air from outside...

that seems pretty simple all the way around with it just being a common water heater .....

thank you


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## Protech (Sep 22, 2008)

I was just thinking that the recirc and tempering tank would be good because of the constant low flow rate and short demand cycles.

each time the guy pulls the trigger, the unit would have to start up if it was on a "once through" design. 

If it's pulling from a small tempering tank with the takagi on a parallel heating loop, the unit will only fire in long cycles on low output to keep the tank temp on target.

If installed with the takagi 1st and then a once through tempering tank, the unit will constantly be switching on and off every time the guy lets go of the trigger. I would think that would be detrimental no?


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## Tankless (Jun 12, 2008)

Dude........

Clean air make up. If the unit has the intake piped up and away from the mist, how is it that you think the mist would screw up the unit? Other than drenching the thing there are no issues. Remember the defination of insanity with your B&W 75. People get woodies over tankless technology. if you have a compeditive bid you stand a much better chance of getting it. This is a pretty simple job and I already told you the best way to do it.....




Master Mark said:


> Tankless..
> 
> from what I am hearing, the mist will screw up a tankless about as fast as the power vent...
> 
> ...


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## Tankless (Jun 12, 2008)

Ken, it works in theory....sorta. Will it work in 5 years from now? How many pumps & tempering tanks will you go through in 10 years? Most of us are smart enough to design for any application. That's not our job, it's to have a solid design that is cost effective that you can stand by. I am a fan of KISS. 




Protech said:


> I was just thinking that the recirc and tempering tank would be good because of the constant low flow rate and short demand cycles.
> 
> each time the guy pulls the trigger, the unit would have to start up if it was on a "once through" design.
> 
> ...


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## ZL700 (Dec 8, 2009)

What's next?.......

..............This is just one way to do it. No pumps for something like this unless there is a recirc line. If there is, now you will really earn it. I designed my own recirc system for tankless systems that I sell as an alternative to the push button Metland system. People who have 5 million dollar houses do not want to push buttons to get hot water. I am not interested in announcing my design to the free world. I did a lot of testing to come up with what I have and will keep it that way. However that said, there is an easier way to do all this. I hate to admit it but this situation may just warrant the dreaded N word. No, not that word, I'm not a racist. The Navien NR 240A is what you want to know about. It's a max load of 200kbtu, built in buffer tank that allowed point of use without always firing up ther burners. This unit also has a built in Armstrong pump (my favorite maker of pumps...hint...hint). PVC venting and DV ready. This is what is called turn key design. The South Koreans did all the work, you just have to install it. Do it by the book because you want that warranty. Find out about commercial applications....I do believe they make a commercial line, that's basically the same thing....it just costs more (shocker).

I have had better luck with the NR series versus the older CR. The CR is obsolete (thank Gawd).

Keep mist OUT of the gas combustion chamber and the water soft and this design will last many years.....barring the Navien takes a self imposed shyit.

The design is the hard part Mark but with some thought and research it's very do-able. The price point with the Navien will most likely help beat your compeditors unless they too are bidding this same design. Good Luck!![/quote]

Sounds good, but the pump is not a Armstrong, it is a SS model made by Navien in Korea


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## DownHill (Oct 15, 2010)

Tankless said:


> Ken, it works in theory....sorta. Will it work in 5 years from now? How many pumps & tempering tanks will you go through in 10 years? Most of us are smart enough to design for any application. That's not our job, it's to have a solid design that is cost effective that you can stand by. *I am a fan of KISS.*


Me too. Provided it meets the demand, a direct vent tank beats it all day long.


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## Protech (Sep 22, 2008)

based on my experience, none.



Tankless said:


> Ken, it works in theory....sorta. Will it work in 5 years from now? *How many pumps & tempering tanks will you go through in 10 years?* Most of us are smart enough to design for any application. That's not our job, it's to have a solid design that is cost effective that you can stand by. I am a fan of KISS.


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