# tank less water heater w/ circ pump



## TNC PLUMBING (Apr 8, 2013)

How do you guys like to set up a circulating pump with a tank less water heater. I've done them on regular tanks with a dedicated return line cut in on the hot. Wondering how the tank less set up works.


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## wyrickmech (Mar 16, 2013)

Look on tannish web sight there is several ways to do it. One I found was to puta small 6 gal electric in the loop all it does is keeps the loop warm between uses.


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## Redwood (Sep 8, 2008)

You do it in accordance with the manufacturers directions if you want your customer to have a warranty....


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## 100 Watt (Aug 11, 2011)

Check out Navien NR240. The pump is already installed inside the unit. They work quite well.


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## PlungerJockey (Feb 19, 2010)

100 Watt said:


> Check out Navien NR240. The pump is already installed inside the unit. They work quite well.


This


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## jc-htownplumber (Feb 29, 2012)

This is what I do


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## rjbphd (Feb 5, 2010)

jc-htownplumber said:


> This is what I do


 Garden hoses connections????


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## bct p&h (Jan 19, 2013)

100 Watt said:


> Check out Navien NR240. The pump is already installed inside the unit. They work quite well.


Not a huge fan of the whole timer deal with those. Whose life is predictable enough to set a timer for when they will need hot water? The way I am going to do my house is an aquastat that only gets powered when you turn on the switch for the bathroom exhaust fan.


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## jc-htownplumber (Feb 29, 2012)

rjbphd said:


> Garden hoses connections????


Haha no they are brass craft bwb25 water heater flexes. I like them a little better than the copper one. They are non conductive, if I don't use them I hard pipe them


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## Titletownplumbr (Feb 16, 2011)

jc-htownplumber said:


> This is what I do


I don't think I would have posted that pic, that's a pretty cobby looking job, it does not look professional.


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## jc-htownplumber (Feb 29, 2012)

Sorry


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## rjbphd (Feb 5, 2010)

jc-htownplumber said:


> Hope it helps


Wow ur phone can read upside-down..


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## jc-htownplumber (Feb 29, 2012)

Yeah I shouldn't of bought it on eBay. I Posted it for him


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## dplumb (Jan 6, 2013)

jc-htownplumber said:


> Haha no they are brass craft bwb25 water heater flexes. I like them a little better than the copper one. They are non conductive, if I don't use them I hard pipe them


Probably cost just as much as a couple female adapters and 3' of pipe, no???


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## dplumb (Jan 6, 2013)




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## jc-htownplumber (Feb 29, 2012)

dplumb said:


> Probably cost just as much as a couple female adapters and 3' of pipe, no???


Yeah probably they cost around 12$-15$ it's what the boss man brought me


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## Joeypipes 23 (Feb 2, 2011)

Nice work


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## dhal22 (Jul 30, 2010)

I've used a Metlund D'mand pump on tankless heaters a few times. Add a motion sensor and you will have a very happy customer. Need to add a pump to my personal tankless, was looking at the Chili Pepper pump but see a lot of bad reviews.

David


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## SHAUN C (Feb 16, 2011)

jc-htownplumber said:


> This is what I do


No 18" coming off the heater?? No drip leg on unit either. Not trying to bust your nuts but we arent allowed to run csst to the unit.


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## Titan Plumbing (Oct 8, 2009)

SHAUN C said:


> No 18" coming off the heater?? No drip leg on unit either. Not trying to bust your nuts but we arent allowed to run csst to the unit.


Ask the inspector what the difference is between CSST and a gas flex...I think you might see his brain melting out of his ears. Also ask you inspector if you have wet or dry gas.

Forever around these parts we never had to run drip/dirt legs, now we have an ex-mech inspector as our chief and he thinks it's the right way to do things, so thats what we do now...

I only use over 50 yrs of actual installations to back up my claim that there is no need for drip/dirt legs in dry gas conditions.


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## JK949 (Mar 18, 2009)

dhal22 said:


> I've used a Metlund D'mand pump on tankless heaters a few times. Add a motion sensor and you will have a very happy customer. Need to add a pump to my personal tankless, was looking at the Chili Pepper pump but see a lot of bad reviews.
> 
> David


Just had the Grundfos rep in today. Metlund will be using Grundfos pumps for their D'mand systems.


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## Joeypipes 23 (Feb 2, 2011)

In NYC unless I'm wrong drip legs are no more and csst is a no no


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## wyplumber (Feb 14, 2013)

Joeypipes 23 said:


> In NYC unless I'm wrong drip legs are no more and csst is a no no


Had a gas line inspection the other day inspector (ex plumber) told me drip legs not required talked to the gas company about it while setting meter he told me always always put in a drip leg


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## wyrickmech (Mar 16, 2013)

wyplumber said:


> Had a gas line inspection the other day inspector (ex plumber) told me drip legs not required talked to the gas company about it while setting meter he told me always always put in a drip leg


It is always a good idea to put a dirt/ drip leg in. The idea that gas is completely dry and without any dirt,oil or trash is not true. There is many variables such as temperature change and flow rates. There can be ice crystals forming in the gas as it goes from warm conditions to cold and you may have the opposite as well. This is the reason for the drip/ dirt leg


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## wyplumber (Feb 14, 2013)

I agree with you Rick I don't know why anyone would skip a drip leg


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## stillaround (Mar 11, 2009)

wyplumber said:


> I agree with you Rick I don't know why anyone would skip a drip leg


1. I dont feel like it comes to mind:laughing:
2. I dont have the parts with me and who knows if they are needed
3. The other heater didnt have it and I just want to use the same fittings...
4. I dont like being told how to do something I know isnt needed........



just a few possible reasons


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## Best Darn Sewer (Dec 23, 2012)

jc-htownplumber said:


> This is what I do


If my boss asked me to use rubber flex hoses like those brass craft ones, I would quit. Your boss doesn't care too much about quality it seems. I don't know your experience level but in all honesty, if I saw this job, I would assume a somewhat skilled handy man installed it and not a licensed plumber. Those flex hoses are just vinyl hoses with a cheap polymer braid around it to make it appear sturdy. They are very prone to leak. Here are some photos of what happens to CPVC when a tankless malfunctions: 






























If this can happen to CPVC, then I can only imagine what would happen to flimsy hoses. You might ought to show your boss these pics and see if he changes his mind. Just a thought.


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## plbgbiz (Aug 27, 2010)

We have been using the braided supplies on WH's for years with no problems.


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## Best Darn Sewer (Dec 23, 2012)

plbgbiz said:


> We have been using the braided supplies on WH's for years with no problems.


At least that use is closer to their intent. They arent meant for a tankless. I would still say a Tankless needs copper all the way to it.


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## love2surf927 (Dec 22, 2011)

I'd say it is more a issue of craftsmanship and pride in your work than anything else, it should work fine but I like to walk away from my work being proud of how it works as well as how it looks, just my two cents....


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## love2surf927 (Dec 22, 2011)

Best Darn Sewer said:


> If my boss asked me to use rubber flex hoses like those brass craft ones, I would quit. Your boss doesn't care too much about quality it seems. I don't know your experience level but in all honesty, if I saw this job, I would assume a somewhat skilled handy man installed it and not a licensed plumber. Those flex hoses are just vinyl hoses with a cheap polymer braid around it to make it appear sturdy. They are very prone to leak. Here are some photos of what happens to CPVC when a tankless malfunctions:
> 
> If this can happen to CPVC, then I can only imagine what would happen to flimsy hoses. You might ought to show your boss these pics and see if he changes his mind. Just a thought.


Those pics are crazy. I almost never see CPVC out here in southern california. I did one install when I was in my first or second year, I wonder how that system is now 9 or 10 years later.


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## TX MECH PLUMBER (May 27, 2011)

This how I do it


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## rjbphd (Feb 5, 2010)

TX MECH PLUMBER said:


> This how I do it


Wtf?? No die electiec unoins???


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## TX MECH PLUMBER (May 27, 2011)

One one recirc line I don't know y a dialectic union was needed the stub out on the heater was brass !! 
. The hot and cold have the brass service valves on them so boss said no unions needed. I haven't done but a hand full of tankless. You could have said good job. A hole !! 
I did hard pipe the gas. I know you like that !!! Lol


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## rjbphd (Feb 5, 2010)

TX MECH PLUMBER said:


> One one recirc line I don't know y a dialectic union was needed the stub out on the heater was brass !!
> . The hot and cold have the brass service valves on them so boss said no unions needed. I haven't done but a hand full of tankless. You could have said good job. A hole !!
> I did hard pipe the gas. I know you like that !!! Lol


I was just razzing ya... good job btw..


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## TX MECH PLUMBER (May 27, 2011)

I know that bro


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## James420 (Nov 14, 2012)

Nice job!! What kind of tankless is that? 

I usually only see Rinnai's and Naivien or Navien what ever it is.


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## TX MECH PLUMBER (May 27, 2011)

Navien. With built in circ pump circs up to 500' of developed length of hot water loop


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## James420 (Nov 14, 2012)

TX MECH PLUMBER said:


> Navien. With built in circ pump circs up to 500' of developed length of hot water loop


I thought they only vented with 3". I wasn't sure as I have only seen a couple of them. Anyway my company only sells the Rinnai, I haven't put either one in yet but from what I've seen the Naiven seems to be an easier installation, plus it comes with a circulation pump. I don't see an advantage in using a Rinnai.

Do the Naviens need a condensate line run as well?


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## TX MECH PLUMBER (May 27, 2011)

Yes on the cond. il run it and t&p after the mechanical contractor sets his boiler. He is setting a hub drain for me and it all goes outside to a French drain 
It vents 2" sch 40 PVC. And combustion air can be as well. There's a louver in the wall so no need for comb air to be ran 

Don't rannia use there own stainless steel vent ? I put a few in even took a class/siminar on them once.


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## JWBII (Dec 23, 2012)

This job I'm doing now will be my first tankless. Pretty neat....

I would have put unions, not for die electric reasons but so if the heater need to be replaced or anything then it can easily be unhooked. I haven't looked inside so I don't know if it can be easily replaced by unhooking inside so I could be talking right outta my ass on this one. I do that frequently lol.

Your work looks great TX by the way. Course I know you know that already


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## Michaelcookplum (May 1, 2011)

jc-htownplumber said:


> This is what I do


Yikes, that looks like a mess


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## Michaelcookplum (May 1, 2011)

That looks a lot better


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## bct p&h (Jan 19, 2013)

James420 said:


> I thought they only vented with 3". I wasn't sure as I have only seen a couple of them. Anyway my company only sells the Rinnai, I haven't put either one in yet but from what I've seen the Naiven seems to be an easier installation, plus it comes with a circulation pump. I don't see an advantage in using a Rinnai.
> 
> Do the Naviens need a condensate line run as well?


The new model vents in 2" and is field convertible between nat and lap
They say you can run ½" gas to it but I wouldn't recommend it.


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## TX MECH PLUMBER (May 27, 2011)

JWBII said:


> This job I'm doing now will be my first tankless. Pretty neat....
> 
> I would have put unions, not for die electric reasons but so if the heater need to be replaced or anything then it can easily be unhooked. I haven't looked inside so I don't know if it can be easily replaced by unhooking inside so I could be talking right outta my ass on this one. I do that frequently lol.
> 
> Your work looks great TX by the way. Course I know you know that already


The service valves I put on for flushing the unit have unions so I put one on the recirc line inlet and the gas. Two pairs of channels and a few min. And she's ready to take off the wall and replace. That is if you can get the same model when this one is broke and thanks I try


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## LeeH (May 11, 2013)

TX MECH PLUMBER said:


> The service valves I put on for flushing the unit have unions so I put one on the recirc line inlet and the gas. Two pairs of channels and a few min. And she's ready to take off the wall and replace. That is if you can get the same model when this one is broke and thanks I try


Those are some expensive and unneeded thermometers on that Navien install when you can walk up to the unit and press the info button and get a cold, hot and GPM digital display reading on the front of the unit, right?


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## LeeH (May 11, 2013)

bct p&h said:


> The new model vents in 2" and is field convertible between nat and lap
> They say you can run ½" gas to it but I wouldn't recommend it.


It will run on 1/2" gas line as long as it has 3.5" W.C. Inlet N/G at full fire.
In other words supply line pressure drops are not as critical as tankless requirements in the past. Losing 2" WC on a 1/2" line starting with 6" is what it's meant to do. 

The new gas code charts now include these higher pressure drop calcs.


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## PlungerJockey (Feb 19, 2010)

LeeH you are making some pretty insightful post, go post an intro and tell us about yourself.

Do you work for Navien, maybe you can give us your input on the issues with the units that have the built in recirc pumps and buffer tanks. It seems they have a problem with water temp fluctuation.


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## plbgbiz (Aug 27, 2010)

LeeH said:


> It will run on 1/2" gas line as long as it has 3.5" W.C. Inlet N/G at full fire.
> In other words supply line pressure drops are not as critical as tankless requirements in the past. Losing 2" WC on a 1/2" line starting with 6" is what it's meant to do.
> 
> The new gas code charts now include these higher pressure drop calcs.


PZ is a site for those already in the plumbing trade. You are welcome to view the site and use the information available to you. Please refrain from posting until you have established that you are active in the trade. 

Thanks.


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## TX MECH PLUMBER (May 27, 2011)

LeeH said:


> Those are some expensive and unneeded thermometers on that Navien install when you can walk up to the unit and press the info button and get a cold, hot and GPM digital display reading on the front of the unit, right?


Yes it reads out all that info. But we designed it for easy maintenance. Don't need some idiot changing set points or screwing with the unit


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## anivaryapump (Aug 21, 2013)

The Energy Factor measures a water heater's overall efficiency by comparing the amount of energy coming in to the heater to the amount of energy it puts out.


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## rjbphd (Feb 5, 2010)

anivaryapump said:


> The Energy Factor measures a water heater's overall efficiency by comparing the amount of energy coming in to the heater to the amount of energy it puts out.


Are you fooking kidding us?... Not a plumber here...


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## TX MECH PLUMBER (May 27, 2011)

anivaryapump said:


> The Energy Factor measures a water heater's overall efficiency by comparing the amount of energy coming in to the heater to the amount of energy it puts out.


Who was talking about energy. Factor ??? Dang goober


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## s.ford (Mar 19, 2014)

Bring your return back to the tankless put the pump on and an aqua stat done deal and all the hot water uneed don't forget your swing checks


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## Will (Jun 6, 2010)

With Navien it's looks like this


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