# Tempering with Circulator



## PlumberDave (Jan 4, 2009)

I've got an am 101 tempering valve and I know that it will not work with a circ system. Any body know an equivalent that will work with a circ system?


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## TX MECH PLUMBER (May 27, 2011)

Is this valve near the water heater ir for a single fixture


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## PlumberDave (Jan 4, 2009)

TX MECH PLUMBER said:


> Is this valve near the water heater ir for a single fixture



it is near the water heater for the whole home.


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## rjbphd (Feb 5, 2010)

PlumberDave said:


> I've got an am 101 tempering valve and I know that it will not work with a circ system. Any body know an equivalent that will work with a circ system?


Why wouldn't it work on circ system?


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## TX MECH PLUMBER (May 27, 2011)

Pipe circ line back into cold inlet on water heater


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## rjbphd (Feb 5, 2010)

TX MECH PLUMBER said:


> Pipe circ line back into cold inlet on water heater


Groans..face bamming the table


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## TX MECH PLUMBER (May 27, 2011)

Wtf RJ. That's how you do it. Unless ur gonna enlighten us on how to do it ?? Dam Yankee


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## PlumberDave (Jan 4, 2009)

Ok commercial guys what tempering valve do you use with a circ hot water system? A standard mixer mixes hot and cold from the water heater to a mix line that we run to fixtures, if you circ the mixed line back to the water heater the temp in the mix line will climb to the hot water temp. because you are not adding any cold water to the mixed system by running mixed hot water.


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## TX MECH PLUMBER (May 27, 2011)

What ever is spect out. Lol

I don't know numbers I see a lot of symmions around here 

You can use the one u have


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## TX MECH PLUMBER (May 27, 2011)

Like this

Some have ports for circ line to tie into valve but its only tied into valve if the gpm is in the correct range


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## rjbphd (Feb 5, 2010)

TX MECH PLUMBER said:


> Like this
> 
> Some have ports for circ line to tie into valve but its only tied into valve if the gpm is in the correct range


Won't work on gravity system


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## TX MECH PLUMBER (May 27, 2011)

Who said any thing about gravity I'm gonna buy you a circ pump and dielectric unions for Christmas. !!!


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## rjbphd (Feb 5, 2010)

TX MECH PLUMBER said:


> Who said any thing about gravity I'm gonna buy you a circ pump and dielectric unions for Christmas. !!!


 Make sure they are Wilco multi speeds pump... die electric unoins.. shiney scraps..


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## TX MECH PLUMBER (May 27, 2011)

Will do


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## TX MECH PLUMBER (May 27, 2011)

I'm bored 

Here's a sketch.


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## rjbphd (Feb 5, 2010)

Isn't ur baby keeping u busy??? 
Per ur stech.. my way is not the aleratvie way.. its the correct way. And btw, the mixing valve are to be at least 25" below the hot water line for it to works properly


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## TX MECH PLUMBER (May 27, 2011)

Baby is asleep. U have ur way. We have ours. Now the 25" below. Never heard that. U mean when the hot turns horizontal after it comes out of the heater ???


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## rjbphd (Feb 5, 2010)

TX MECH PLUMBER said:


> Baby is asleep. U have ur way. We have ours. Now the 25" below. Never heard that. U mean when the hot turns horizontal after it comes out of the heater ???


No,, pipe whatever the hot water needed to go ( high temps).. then feed off of it by dropping 25" into the mixing valve... I think Watts or Holbey have drawing on this.. and learned my mistake...


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## TX MECH PLUMBER (May 27, 2011)

Is this on all brands or only some so u just do it all the time 

Like this ?


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## rjbphd (Feb 5, 2010)

Yep! That's the way most manufactor want!


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## luv2plum (May 16, 2012)

I would like to respectfully disagree with both RJ and Tex, but just for discussion purposes.

Here is how we generally plumb in a recirc system with a thermostatic mixing valve:
http://www.cashacme.com/_images/pdf...ostatics/General/MG_Recirculating_Diagram.pdf

Plumbing it this way, the circulator moves water through both the hot and cold inlets of the valve, which prevents it from "locking up" during periods of no demand in the building. We have re-piped several systems that were not working correctly, and when we use the configuration shown in the diagram, it has always worked flawlessly. 

To demonstrate what happens when recirc only flows through hot side of the mixing valve, picture this scenario:

There is no demand for hot water in the building, and recirc is only flowing through the hot side of the mixing valve (piped as shown in Tex's diagram). Water heater set point is 140F, tempering valve set at 120F discharge temperature. 120F (or a bit less due to heat loss) water returns from the building, then into the water heater where it gets heated and comes out at 140F. This 140F water enters the hot inlet of the tempering valve. The tempering valve closes the hot side and opens to the cold side, trying to drop the temp of the water to it's 120F setting. There is no flow on the cold side however, since recirc is only piped into the hot (the inlet of the water heater). 

At this point, the tempering valve can only do 2 things: 1) close off the hot side completely and open cold completely, therefore stopping recirc flow altogether until the recirc line loses enough temp through heat loss thus allowing the hot side to open again momentarily, or 2) keep the hot side open a little bit, thus allowing the recirc line and entire DHW system temperature to eventually rise to the 140F tank temp until someone uses hot water again and the cold can be mixed in.


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## TX MECH PLUMBER (May 27, 2011)

Hum. I didnt know that. Il have to read up on that some. Ya learn every day. Even from a def Yankee. Lol. Good looking out RJ. I wouldn't expect less of you to always find something wrong with my drawings/installs. You have truly made me a better plumber. As hole Nite


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## redbeardplumber (Dec 4, 2012)

I learn a lot when you two banter about, keep it up. 
Excuse my ignorance... In your diagramn is the recirq coming off of hot water or tempered water?
I'm assuming tempered


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## TX MECH PLUMBER (May 27, 2011)

Tempered. But it could come off both at the same time or just the hot Cause its gonna be heated and tempered again. I think. Baby's up. I need sleep


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## justme (Jul 4, 2012)

The bradley navigator mixing valve is what we usually submit for use.


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## justme (Jul 4, 2012)

Every valve is different


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## TX MECH PLUMBER (May 27, 2011)

This is a navigator if a remember correctly.


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## MTDUNN (Oct 9, 2011)

TX MECH PLUMBER said:


> Wtf RJ. That's how you do it. Unless ur gonna enlighten us on how to do it ?? Dam Yankee


That's how I do it. It's not gonna be gravity obviously


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## MTDUNN (Oct 9, 2011)

TX MECH PLUMBER said:


> I'm bored Here's a sketch.


Even my 13 year old understood this drawing

.


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## TX MECH PLUMBER (May 27, 2011)

Is that good ?


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## MTDUNN (Oct 9, 2011)

No, he is a TAG student. His brain is constantly hungering. He's smart but there is a difference between intelligent and common sense which he has none at all.

Edit: about your drawing? Yes I can see your experience on that paper.


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## love2surf927 (Dec 22, 2011)

Shouldnt the check be downstream of the pump, and I always add a hose Bibb after the check and another bv after that to allow purging through the pump. I was always taught check downstream of pump which makes sense to me.


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## love2surf927 (Dec 22, 2011)

luv2plum said:


> I would like to respectfully disagree with both RJ and Tex, but just for discussion purposes.
> 
> Here is how we generally plumb in a recirc system with a thermostatic mixing valve:
> http://www.cashacme.com/_images/pdf_downloads/products/thermostatics/General/MG_Recirculating_Diagram.pdf
> ...


That's quite a piping arrangement but it makes sense!!


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## Plumbus (Aug 4, 2008)

justme said:


> Every valve is different


Every valve may be different, but Caleffi, Powers, and Apollo all show schematic drawings that conform to the Bradley and Cash Acme drawings displayed above. I think this is confirmation that this is the proper method for installing an ASSE 1017 valve. And, that's the way I've been instructing my guys to plumb them.


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## justme (Jul 4, 2012)

Plumbus said:


> Every valve may be different, but Caleffi, Powers, and Apollo all show schematic drawings that conform to the Bradley and Cash Acme drawings displayed above. I think this is confirmation that this is the proper method for installing an ASSE 1017 valve. And, that's the way I've been instructing my guys to plumb them.


You mean you won't be installing the mixing valves 25" below the heater or throw the recirc pump out and put in a gravity system?


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## Plumbus (Aug 4, 2008)

justme said:


> You mean you won't be installing the mixing valves 25" below the heater or throw the recirc pump out and put in a gravity system?


:laughing::laughing::laughing:

If you follow the manufacturer's installation directions, if something goes wrong they can't come back and say you screwed up the install.


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## Plumbus (Aug 4, 2008)

love2surf927 said:


> Shouldnt the check be downstream of the pump, and I always add a hose Bibb after the check and another bv after that to allow purging through the pump. I was always taught check downstream of pump which makes sense to me.


Grundfos installs their built in check on the pump outlet. 
This is the easy way to add a hose bib-bleeder.
http://www.webstonevalves.com/default.aspx?page=customer&file=customer/wecoin/customerpages/isolator_drain.htm


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## love2surf927 (Dec 22, 2011)

Plumbus said:


> Grundfos installs their built in check on the pump outlet.
> This is the easy way to add a hose bib-bleeder.
> http://www.webstonevalves.com/default.aspx?page=customer&file=customer/wecoin/customerpages/isolator_drain.htm


Nice setup thank you for that tip.


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## B Rohr (Nov 6, 2013)

*proper piping required*

there are a few critical details when piping recirc to thermostatic valve. I learned of this method from a PM Mag article back in 2002. Julius Ballanco, an engineer, was the author and he deals with scald lawsuits.

One of two problems can occur, either temperature creep, or temperature droop. Most all thermostatic manufacturers have the proper piping schematic online. Basically it involves a small crossover line and a balance valve.

I will disclose that I work for Caleffi, a manufacturer. We publish a technical journal twice a year and have an excellent issue that deals with DHW mixing and recirc. Take a look.

http://www.caleffi.us/en_US/caleffi/Details/Magazines/pdf/idronics_11_us.pdf


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## rjbphd (Feb 5, 2010)

You 'sound' familier... over at the heatinghelp forum ??? You made a worthy statement and do remembered reading that article back then... however, to be wholeheartly welcomed here, you gotta post a introduction...


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## Plumbus (Aug 4, 2008)

rjbphd said:


> You 'sound' familier... over at the heatinghelp forum ??? You made a worthy statement and do remembered reading that article back then... however, to be wholeheartly welcomed here, you gotta post a introduction...


Bob
Don't say I didn't warn you.


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## TX MECH PLUMBER (May 27, 2011)

luv2plum said:


> I would like to respectfully disagree with both RJ and Tex, but just for discussion purposes.
> 
> Here is how we generally plumb in a recirc system with a thermostatic mixing valve:
> http://www.cashacme.com/_images/pdf_downloads/products/thermostatics/General/MG_Recirculating_Diagram.pdf
> ...


It makes sense. And I've seen it n eye wash stations and a few other times. But I do t think you can do it that way on all mixing valves. On low flow systems yes. It all depends on the mixing valve and what it's being used for. Some the recirc line temp would be higher then the range for the cold water inlet on the valve and it would not work properly. On a large com restaurant or cafeteria I don't think it wold work 

Good point tho


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## Plumbworker (Oct 23, 2008)

Heres a interesting read on the subject..

http://www.plumbingengineer.com/may_10/code.php

i think this is the article hot rod rohr was talking about as well..


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