# Going Tankless



## PunkRockPlumber (Mar 26, 2012)

I'm installing my first tankless water heater. Actually replacing a traditional water heater with a tankless. I was wondering if the flue for the tankless was of a different rating or can I use the same type?


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## easttexasplumb (Oct 13, 2010)

Depending on the type and brand of tankless most manufactors have their own specific flues. I do not know of any that use type B vent material. The flue kits for most tankless are very expensive.


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## PunkRockPlumber (Mar 26, 2012)

easttexasplumb said:


> Depending on the type and brand of tankless most manufactors have their own specific flues. I do not know of any that use type B vent material. The flue kits for most tankless are very expensive.


Thanks, I'm writing up an estimate for a remodel and trying to figure in the flue for the tankless. I'll have to get some prices if you say it's very expensive.


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## JK949 (Mar 18, 2009)

Please call your local rep for the manufacturer you're installing. You shouldn't be asking this question if you know what you are doing.


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## PunkRockPlumber (Mar 26, 2012)

JK949 said:


> Please call your local rep for the manufacturer you're installing. You shouldn't be asking this question if you know what you are doing.


Said it was my first tankless I'd be installing. Thanks for the input.


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## Plumb Bob (Mar 9, 2011)

Read the installation manual, every brand is different. Most manuals are available online


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## Plumbdog (Jan 27, 2009)

^^^^^^ What he said!


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## Plumber (Jan 18, 2009)

MikeBKNY78 said:


> Said it was my first tankless I'd be installing. Thanks for the input.


This is the Age of e-Information. People expect you to search for the answer and not to ask. If you do ask, you are considered dumb and they will let me know. This has happened to me more than a few times.

I would rather learn from a forum than from a stranger, but it is discouraged.

This Age has also created instant faux-geniuses. These are people who search out answers to questions and post it in their own words. There was one major one here for a while.

To answer your question, tankless has their own specs, top to bottom. It's different than tanks and has a learning curve. Find a great supplier who is willing to help you.


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## Plumb Bob (Mar 9, 2011)

You will also more than likely have to upgrade gas line. It will need to be sized to accommodate new tankless w/h


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## JK949 (Mar 18, 2009)

I actually expect people to go through the manufacturer training that is routinely offered at supply houses all over.

Have you decided which brand and model you are going to install?

How many showers in the home?

Incoming water temperature? Most flow numbers are based on a 45 degree rise in temperature, some dip down the 35 to fluff the numbers. Wrong size unit may present challenges in winter months.

Is there hard water? Do you know the service schedule so the exchanger soesn't fail prematurely?

Know the max BTU demand of the unit and run the numbers for the gas system to be sure. 3/4" will serve a 199,000 BTU system up to 30' by UPC code. Any further and you need 1"

Venting: Most require stainless steel. Unless it's fully condensing then you have options for PVC. 

Rinnai uses a proprietary system, pipe inside a pipe. They have two styles for standard and fully condensing units.

So again contact the local rep and get the low down.


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## user2090 (Sep 26, 2009)

My first gas tankless was a condensing one with PVC for venting. Wouldn't even waste my time quoting anything else. 

By the way it was a Navien and went in super easy, no problems. 

Keep in mind.

Gas requirements - Vent Requirement - Isolation valves - SIZE, SIZE, SIZE beware the flow rates for tankless. They mislead with a unreasonable minimum rise and GPM. If you undersize your gonna have a pissed off customer. 

9.4 GPM at rise of 40 degrees sounds nice until you consider 55 degree incoming water. GPM drops like lead balloon when more rise is needed.


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## Eric (Jan 10, 2011)

What brand are you looking at pricing?


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## Pipecommandor (Apr 18, 2011)

Noritz


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## SewerRatz (Apr 25, 2009)

JK949 said:


> Please call your local rep for the manufacturer you're installing. You shouldn't be asking this question if you know what you are doing.





MikeBKNY78 said:


> Said it was my first tankless I'd be installing. Thanks for the input.


 

Hey JK949 is not joking or being a smart ass. Call the local rep take their install class. Most manufactures will not warranty a unit if not installed by a certified installer.

Asking about venting material shows you never taken any of the free classes that all the manufactures offer. They will teach you about venting , gas pipe sizing, and picking the right unit or units for the job. I have followed behind 100's of plumbers that installed a tankless incorrectly and fixed their mistakes.


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## Don The Plumber (Feb 14, 2010)

C'mon, tankless units are so easy to install, that its almost impossible to screw them up. Anyone can do it. Here's your proof.


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## PunkRockPlumber (Mar 26, 2012)

Thanks.


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## PunkRockPlumber (Mar 26, 2012)

Eric said:


> What brand are you looking at pricing?


Just picked it up. Navien Condensing NP-240A. PVC Venting. Sweet.


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## Cal (Jun 17, 2008)

Have you looked into these ? ;

http://eternalwaterheater.com/

Truly are better then regular tankless , price is almost no difference, uses some better technology to allow for consistent pressure / volume .

just a thought


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## johnlewismcleod (Apr 6, 2012)

Rheem has a new condensing unit w/ pvc venting as well...it's got a good low flow trip setting.

Be very careful about retro fitting tankless: if the gas supply is insufficient due to being piped for tank type, or the city supply chokes down in cold weather due to city piping being undersized...you will have problems.

I put a few good units in near downtown Dallas during the summertime when the available gas pressure was fine, only to get call backs during cold snaps in the winter when the units malfunctioned due to low gas pressure.

Some of the cheap ones (Home Depot and Lowes) have high flow requirements (.5 - .3 gal/min) and won't fire when low flow lav's are used :thumbdown:


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## johnlewismcleod (Apr 6, 2012)

Cal said:


> Have you looked into these ? ;
> 
> http://eternalwaterheater.com/
> 
> ...



The ten gallon/minute flow of the retrofit version may be problematic for filling baths. I'd be leery of these until I saw how they perform with women in the house trying to bath


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## Cal (Jun 17, 2008)

johnlewismcleod said:


> The ten gallon/minute flow of the retrofit version may be problematic for filling baths. I'd be leery of these until I saw how they perform with women in the house trying to bath


John ,, most houses should opt for the 145s or 195s models . The 100s is really for those little houses with 1 + 1/2 bath ,kit,laundry . 

The rebates are still good , the freakin thing inside is made from the heaviest stainless steel ,, aircraft stuff or something !
What i also like is there are two ports on top . One is exhaust vent ( MUST BE RUN PROPERLY ! ) 2" or 3" . The other port is intake air ,, if room is large enough you don't have to run a thing . Make sure there is plenty of make up air and off you go ! 

Water lines come in from the top ,, no piping all over the place with into expensive valve kits ,etc 

Just a thought and an option


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## Master Mark (Aug 14, 2009)

Cal said:


> John ,, most houses should opt for the 145s or 195s models . The 100s is really for those little houses with 1 + 1/2 bath ,kit,laundry .
> 
> *The rebates are still good ,* the freakin thing inside is made from the heaviest stainless steel ,, aircraft stuff or something !
> What i also like is there are two ports on top . One is exhaust vent ( MUST BE RUN PROPERLY ! ) 2" or 3" . The other port is intake air ,, if room is large enough you don't have to run a thing . Make sure there is plenty of make up air and off you go !


 
Perhaps I am wrong, but did not those rebates get
hacked down to only 500 bucks from a high of 1500 starting at the first of this year??:yes:

I guess as long as their is even a hint of something back people will still go ape-crazy for the product...

all it means is it will take another 10 years to break even on one, and with the cost of natrual gas tanking
to under half of what it was 3 years ago, its a real bargain to go tankless....

yeaaaaa baby...


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## Cal (Jun 17, 2008)

Mark ,, ya know i'm not saying it's as cheap as a regular tank type . Just another "endless hot water " option that really seems to have worked out a few "tankless" kinks . 
The wife & I are empty nesters ,, my b.w. 50 gas is 12-14 yrs . I'm getting a nice price on a 145 model and will be installing it after a while . Since the labor is free ;-)


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## Master Mark (Aug 14, 2009)

Cal said:


> Mark ,, ya know i'm not saying it's as cheap as a regular tank type . Just another "endless hot water " option that really seems to have worked out a few "tankless" kinks .
> The wife & I are empty nesters ,, my b.w. 50 gas is 12-14 yrs . I'm getting a nice price on a 145 model and will be installing it after a while . Since the labor is free ;-)


I hear what you are saying.... 
since your labor is free
and you probably will get a good deal from your supply house...cost...

and odds are you know what you are doing...:whistling2::laughing:

its a win -- win for you

as long as the wife is happy with the outcome
and how it works, you are looking good


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## pilot light (Apr 21, 2012)

you guys ever used centrotherm? great stuff!


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## Cal (Jun 17, 2008)

pilot light said:


> you guys ever used centrotherm? great stuff!


 Never heard of it or them ,,, what it be ??


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## pdxplumber (Nov 21, 2009)

I have installed two 145 btu Eternals and they work great. Very easy install after reading the manual. Great for retrofit with overhead water. They perform just about the same as a tank type heater. And they look bad ass.


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## pilot light (Apr 21, 2012)

Cal said:


> Never heard of it or them ,,, what it be ??


It is from europe, replaces pvc and cpvc venting is sold both in ridgid and flexiable. On the vertical It can be flexiable to get down that offset chimmey it is also rated in temp higher than pvc and cpvc! Its made of poly-propelene and is glueless with gasketed joints and locking ring. Same maker as Aquatherm!


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## PunkRockPlumber (Mar 26, 2012)

JK949 said:


> Please call your local rep for the manufacturer you're installing. You shouldn't be asking this question if you know what you are doing.


Im attending Navien installation and service seminar Thursday.


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## johnlewismcleod (Apr 6, 2012)

pdxplumber said:


> I have installed two 145 btu Eternals and they work great. Very easy install after reading the manual. Great for retrofit with overhead water. They perform just about the same as a tank type heater. And they look bad ass.


On 1/2" IP feed or 3/4"? How many inches of w.c. were available? Have they been in through winter weather yet?

Just curious...I like tankless technology and like to keep abreast of what works


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## johnlewismcleod (Apr 6, 2012)

MikeBKNY78 said:


> Im attending Navien installation and service seminar Thursday.


I've had good luck with the new Naviens :thumbsup: , but having said that I ran the gas new myself, so that wasn't and issue 

The one thing that does concern me a bit is the built in circulation pump...they look good and have worked well for about a year now, but I can't help but wonder how difficult it will be to change then (no to mention diagnose them) if they fail.

I put in a couple of the new condensing Rheems recently and installed without storage (besides the fairly large piping system) and a circulation pump. Worked brilliantly due to the .15 gal./min. flow trip. I like that I can change the pump without opening the heater should the need arise.


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## pdxplumber (Nov 21, 2009)

1" iron pipe for the gas. Thankfully Hvac contractors are running more 1" gas for the furnace anticipating tankless upgrades. Inches of w.c.? I have no idea, i dont own a manometer ( i think thats what its called) I know the gas company supplies the correct pressure range from their meter. I had one customer use the Eternal through the winter and they love it. No problems so far. I have a plumber friend who has installed at least a dozen and he has had some trouble. Not sure how it worked out for him.


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## TX MECH PLUMBER (May 27, 2011)

Around here with furnace and instant water heater I think it's around 12in w.c. I mite be wrong tho


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## johnlewismcleod (Apr 6, 2012)

12" w.c. would be too high, 10" is max for Navien and most furnaces.

Usually building pressure is set at around 7 - 8 inches.

Manometers are very useful for tankless installs...if the regulator is set at 7.5" and you suspect (or know) the piping is restricting you can go to the regulator and dial it up to 9.5 -10" w.c. 

Maybe by doing this you could get by with a 145 Eternal on 1/2" IP retrofit as long as the city pressure and water temperature doesn't drop too much in cold snaps


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## TX MECH PLUMBER (May 27, 2011)

I stand corrected. I don't do service at all but boss sends me to county jail to check out rainni water heaters the heat exchanger was leaking on both units and ruined the burner and blower on one and burner on the other. I Checked the gas pressure and every thing and finally figured the pressure switch was bad too. With the help of the tech support guy. I got it done tho!! Can you picture it. And commercial mech plumber repairing a compact as hell instant water heater. All I had was the book and a tech support number!!! I was ver proud of my self. I had to pull all the circuit boards out and basically rip it apart and teach my self how it all worked and that they where slaves together !!


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## PunkRockPlumber (Mar 26, 2012)

Navien training update: I'm the only schmuck here.


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## easttexasplumb (Oct 13, 2010)

MikeBKNY78 said:


> Navien training update: I'm the only schmuck here.


 
Hope it is not a sales seminar, make the rep buy your lunch.


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## Qball415 (Nov 20, 2010)

MikeBKNY78 said:


> Navien training update: I'm the only schmuck here.


If your the only schmuck, how many Plumbers showed up?


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## SewerRatz (Apr 25, 2009)

If you are the only one there, take full advantage of it. Ask lots of questions, have him give you a hands on taking the unit apart and troublshooting it. You will need these skills if you are putting in ju.. er I mean Navien units.


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## johnlewismcleod (Apr 6, 2012)

MikeBKNY78 said:


> Navien training update: I'm the only schmuck here.


Ha!:laughing:

But really that's a good thing! You get trained up with personalized attention and then you can walk me through a pump diagnose/change out when it comes up in the future, right?


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## MTDUNN (Oct 9, 2011)

Plumber said:


> This is the Age of e-Information. People expect you to search for the answer and not to ask. If you do ask, you are considered dumb and they will let me know. This has happened to me more than a few times.
> 
> I would rather learn from a forum than from a stranger, but it is discouraged.
> 
> ...


Also ask the suppliers distributor


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## MTDUNN (Oct 9, 2011)

Don The Plumber said:


> C'mon, tankless units are so easy to install, that its almost impossible to screw them up. Anyone can do it. Here's your proof.
> 
> https://www.ridgidforum.com/forum/attachments/16611d1333511235-20120403_164433[1].jpg


This picture looks fuzzy on my phone. Is that a propane tank?


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## MTDUNN (Oct 9, 2011)

I think that is correct


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## PunkRockPlumber (Mar 26, 2012)

Qball415 said:


> If your the only schmuck, how many Plumbers showed up?


Lol funny! Shouldn't you be on intro patrol?


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## 89plumbum (May 14, 2011)

MikeBKNY78 said:


> Navien training update: I'm the only schmuck here.


Are you sure your not at the sharkbite certification??


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## PunkRockPlumber (Mar 26, 2012)

89plumbum said:


> Are you sure your not at the sharkbite certification??


Comedians.


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## Don The Plumber (Feb 14, 2010)

MTDUNN said:


> This picture looks fuzzy on my phone. Is that a propane tank?


Yes


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## johnlewismcleod (Apr 6, 2012)

SewerRatz said:


> If you are the only one there, take full advantage of it. Ask lots of questions, have him give you a hands on taking the unit apart and troublshooting it. You will need these skills if you are putting in ju.. er I mean Navien units.



This :thumbsup:


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## affordabledrain (Nov 24, 2009)

How did the install go?


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## PunkRockPlumber (Mar 26, 2012)

Still waiting for the job to start. Township is giving the GC trouble with permits.


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## affordabledrain (Nov 24, 2009)

dang. that sucks. went thru all that grief to only sit and wait.


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## BigDave (Mar 24, 2012)

Cal said:


> Have you looked into these ? ;
> 
> http://eternalwaterheater.com/
> 
> ...


Good customer service, very few lemons!

Pros:
All stainless piping and heat exchanger means no annual flushing required.
Vents with PVC pipe.
Full 20 year warranty on heat exchanger.
Full diagnostic software on motherboard, gives on the fly temperature
readings for intake air, incoming water, burner chamber, & outgoing water.
As well as GPM flow rate. 

Cons:
Very sensitive on gas pressure, make sure it's right.
Loud if intake is not piped to outside, had complaints!
Claims to fire burner with 1/10th gallon per min. flow rate,
but found taking restrict out of shower heads ends all complaints
of cold water sandwich.


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