# Multiple primary/secondary piping arrangements



## Catlin987987

We are installing two RBI Futera II 1950MBH. The RBI manual prefers the 2nd image. I was wonder the differance between what I was going to pipe (image 1) vs image 2.








VS


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## Gettinit

First off it is only a suggested piping diagram. As long as it meets codes, within reason, you should be fine. With that being said, theirs looks neater and it has the same temperature entering and exiting all of the units whether it be two or ten. Your way, each boiler after the first will see higher temps the more boilers you have. May not amount to anything even with 20 boilers but it is different. Also (not in your case) their may be a spacing issue with the tee's. 

I will assume there is more to the near boiler piping than what is illustrated, ie. balancing valves. 

Just my 2 cents.


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## Catlin987987

Gettinit said:


> First off it is only a suggested piping diagram. As long as it meets codes, within reason, you should be fine. With that being said, theirs looks neater and it has the same temperature entering and exiting all of the units whether it be two or ten. Your way, each boiler after the first will see higher temps the more boilers you have. May not amount to anything even with 20 boilers but it is different. Also (not in your case) their may be a spacing issue with the tee's.
> 
> I will assume there is more to the near boiler piping than what is illustrated, ie. balancing valves.
> 
> Just my 2 cents.


If the injection pumps are controlled by the Tekmar do you think you think is a need for balancing valves? How much of a difference of temperature entering and exiting could you really see? The way I see it, if each pipe is 2-1/2" (image 1) how beneficial would it be having another 4" loop (image 2) as per RBI?


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## rjbphd

Incorrent boiler piping in the drawing... period


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## MarkToo

It's a series vs parallel setup.

Drawing 1 will work the first boiler much harder than the second. 

Drawing 2 (pseudo parallel), will share the load evenly between the two heat sources.


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## UA22PLumber

this is how I would do it..

btw.....diagram 1 is not in series.....diagram 2...could allmost be parallel


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## OldSchool

Both drawings are parallel ....

They are the same ... In Essence 

Drawing one will use smaller pipe to tie into the main 

As the other one would need the same pipe size as the main where they tee together


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## Gettinit

UA22PLumber said:


> this is how I would do it..
> 
> btw.....diagram 1 is not in series.....diagram 2...could allmost be parallel


Never mind that last comment.


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## Gettinit

Catlin987987 said:


> If the injection pumps are controlled by the Tekmar do you think you think is a need for balancing valves? How much of a difference of temperature entering and exiting could you really see? The way I see it, if each pipe is 2-1/2" (image 1) how beneficial would it be having another 4" loop (image 2) as per RBI?


I cannot comment as to the temperature and exactly how much harder one would work compared to the others, but I know they will not work the same, even with the balancing valves. The higher the temps the wider the gap there will be between which is working harder.

I do not understand what you mean by an extra 4" loop. There should be one loop passing by the boilers and you should just be tying into that. I think balancing valves are the way to go on any system that has more than one boiler. I would also put one at every hot water coil. If I am not mistaken RBI will likely want or more so require you to have the balancing valves. If you are unsure just call RBI.


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## UA22PLumber

> Never mind that last comment


I was just getting my rebuttal typed up too..........


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## ZL700

UA22PLumber said:


> this is how I would do it..
> 
> btw.....diagram 1 is not in series.....diagram 2...could allmost be parallel


Much better

Larger connecting pipes but better flow/temp balance


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## UA22PLumber

Just for my own curiosity... why install 85% eff. boilers?... I can't remember the last time I installed a non-condensing boiler.


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## ZL700

When required to run higher temps, no condensing takes place. Waste of money for an appliance that never gets over 90%. 
Outdoor reset helps but it depends on S&R DT and amount of time running in a lower temp condensing mode. 

Same argument with a hybrid car, buy one and drive under 8,000 miles a year or so and the added cost offered no savings


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## MarkToo

UA22PLumber said:


> this is how I would do it..
> 
> btw.....diagram 1 is not in series.....diagram 2...could allmost be parallel



No, it's not true series but, the effect is similar in that it will work one unit harder than the other.

Edit:. Nevermind. I didn't pay attention to the main loop connections in the diagram. It's not what I thought I saw initially. No its not series piped.


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## Catlin987987

UA22PLumber said:


> Just for my own curiosity... why install 85% eff. boilers?... I can't remember the last time I installed a non-condensing boiler.


 in Edmonton all the buildings are designed for 180F water. Most buildings have baseboard fin. The boilers only run at 140F for a few months per year, the cost savings vs the higher boiler cost/servicing would take years(if at all) to recoup.



Gettinit said:


> I think balancing valves are the way to go on any system that has more than one boiler. I would also put one at every hot water coil. If I am not mistaken RBI will likely want or more so require you to have the balancing valves.


The pumps run when there is a call for heat. The pumps will pull as much water as they are sized, if sized correctly, there shouldn't be a need for balancing valves.



OldSchool said:


> Both drawings are parallel ....
> 
> They are the same ... In Essence
> 
> Drawing one will use smaller pipe to tie into the main
> 
> As the other one would need the same pipe size as the main where they tee together


That's what I was thinking.



UA22PLumber said:


> this is how I would do it..
> 
> btw.....diagram 1 is not in series.....diagram 2...could allmost be parallel


That's basically the same think, just drawn better. I do see how the primary mains are different, I just didn't draw them that way.



MarkToo said:


> It's a series vs parallel setup.
> 
> Drawing 1 will work the first boiler much harder than the second.
> 
> Drawing 2 (pseudo parallel), will share the load evenly between the two heat sources.


The tekmar will cycle the boilers to evenly share the load. IE first on/first off, and rotating them



rjbphd said:


> Incorrent boiler piping in the drawing... period


How would you do it?


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## Gettinit

No pumps are ever sized properly. Everybody usually oversizes everything.....when engineers get involved.


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## Catlin987987

Gettinit said:


> No pumps are ever sized properly. Everybody usually oversizes everything.....when engineers get involved.


We size our pumps for what the boiler requires @20f delta tee. Plus a few feet of head for piping on 2nd speed. If needed we can go to the third speed.


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## Catlin987987

Any responses or other comments appreciated.


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## Gettinit

Off topic.....is it not a moot point, don't you have to install it by the engineers prints anyhow?


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## Catlin987987

Gettinit said:


> Off topic.....is it not a moot point, don't you have to install it by the engineers prints anyhow?


Its a retrofit. There are no engineers involved. Where taking out two 2,000MBH raypaks and installing Two RBI Futera II 1,950 MBH.


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## ZL700

Gettinit said:


> No pumps are ever sized properly. Everybody usually oversizes everything.....when engineers get involved.


Wow, that was a blanket statement 

I could group some bad plumbers also into that type of talk :thumbup:


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## Gettinit

ZL700 said:


> Wow, that was a blanket statement
> 
> I could group some bad plumbers also into that type of talk :thumbup:


Sorry. I guess it was a poor choice of words. It just seems like through the process each person involved bumps them up a few percent to cover themselves. As far as plumbers, I don't know many plumbers (personally around here) that even know how to read a pump curve. I have personally seen plumbers and HVAC contractors either get the same pump because it was there already or going bigger because "bigger is better".


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## Gettinit

I feel like I am digging a hole...


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## ZL700

Gettinit said:


> I feel like I am digging a hole...


No problem

Doctors misdiagnose, lawyers don't remember every judicial case precedent and some engineers shouldn't practice all disciplines.


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## chuckscott

Catlin987987 said:


> Any responses or other comments appreciated.



The only difference I can see is that the #2 pipe lengths look similar, and, in theory (theory in my head) it would wear each tank equally. Same theory when piping residential wh in parallel. at least that's what I was taught. 

I am wondering if UA22PLumber's diagram would offer same benefit? Looks like series/parallel... seralell? peries?:laughing: I must admit doing a double take on this one..


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## rjbphd

chuckscott said:


> The only difference I can see is that the #2 pipe lengths look similar, and, in theory (theory in my head) it would wear each tank equally. Same theory when piping residential wh in parallel. at least that's what I was taught.
> 
> I am wondering if UA22PLumber's diagram would offer same benefit? Looks like series/parallel... seralell? peries?:laughing: I must admit doing a double take on this one..


 That's a correct way..


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## chuckscott

rjbphd said:


> That's a correct way..




Maybe I am over analyzing this. It's one thing to look at a diagram and a totally other one when seen installed. At least in my case that is. 

All of my boiler work is repair. I just started with new company that actually installs. May try to get in on a couple installs, or at least pay attention to the existing ones I work on:whistling2:


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## UA22PLumber

> I am wondering if UA22PLumber's diagram would offer same benefit? Looks like series/parallel... seralell? peries?:laughing: I must admit doing a double take on this one..


It's called "Reverse Return",basically, this piping arraingment gives you the benefits of a "parallel" system ,that can actually be piped in the real world....It's pretty easy to show a couple of boilers on a print,where all the piping looks nice and symetrical,equa-distance to both boilers (Parallel)...but in reality, when you have 2 boilers sitting next to each other in a mechanical space,with all the other crap that has to be in there,using exactly the same lengths of pipe and numbers of fittings to each boiler can be next to impossible."Reverse Return" alleviates some of the inherent piping restrictions imposed by a parallel system.
And when you get into systems that have 3,4...or more boilers,Reverse return is about the only way to ensure equal load to all boilers.


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## U666A

UA22PLumber said:


> It's called "Reverse Return",basically, this piping arraingment gives you the benefits of a "parallel" system ,that can actually be piped in the real world....It's pretty easy to show a couple of boilers on a print,where all the piping looks nice and symetrical,equa-distance to both boilers (Parallel)...but in reality, when you have 2 boilers sitting next to each other in a mechanical space,with all the other crap that has to be in there,using exactly the same lengths of pipe and numbers of fittings to each boiler can be next to impossible."Reverse Return" alleviates some of the inherent piping restrictions imposed by a parallel system.
> And when you get into systems that have 3,4...or more boilers,Reverse return is about the only way to ensure equal load to all boilers.


Is this similar to what I've heard referred to here as "first in, last out"?


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## UA22PLumber

gah


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## UA22PLumber

First in Last out could also apply to a manifold arraingment like this.


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## rjbphd

More elbows on red pipings, increasing the TEL...


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## knuckles

This may be a dumb question.
Whats with all the parallel and reverse/return talk all about. Isnt this primary secondary?
You could put the boilers on oppisite ends of the building and they would work fine. The only issue i see would be pipe sizing, pump sizing and distance between the t's on the main.
I need to study up on my pump stuff because im getting confused.


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## rjbphd

knuckles said:


> This may be a dumb question.
> Whats with all the parallel and reverse/return talk all about. Isnt this primary secondary?
> You could put the boilers on oppisite ends of the building and they would work fine. The only issue i see would be pipe sizing, pump sizing and distance between the t's on the main.
> I need to study up on my pump stuff because im getting confused.


 Get the book!!


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## knuckles

rjbphd said:


> Get the book!!


thanks for the help dude


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## rjbphd

knuckles said:


> thanks for the help dude


 There are 2 books... one is " Pumping Away" and other is IBR heating book... both can be purchased thru Dan Holohan's Heating Help website...


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## knuckles

Cool. So while im waiting on the books can you explain the purpose of the parallel and reverse/return piping on a primary secondary heating loop?


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## Gettinit

Here is one to get shot down but my honest opinion for primary/secondary....size the pumps in the system properly, balance the system, and all you really need are triple duty valves.


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## rjbphd

Gettinit said:


> Here is one to get shot down but my honest opinion for primary/secondary....size the pumps in the system properly, balance the system, and all you really need are triple duty valves.


Triple duty valve??? U mean a three way thermosataic valve??


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## Gettinit

Triple duty valve

Just so we are on the same page with the jargon....


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## rjbphd

Gettinit said:


> Triple duty valve
> 
> Just so we are on the same page with the jargon....


Thanks.. never seen them around this part and yet, the headqtr is 20 miles from me...


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## Gettinit

I have a couple of boiler books but they didn't hit on much for me. It may be a good read for guys like ZL700 though. They were pricy too. I use them when I need to sleep.


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## rjbphd

Gettinit said:


> I have a couple of boiler books but they didn't hit on much for me. It may be a good read for guys like ZL700 though. They were pricy too. I use them when I need to sleep.


 Which one are they??


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## Gettinit

Industrial burners handbook and The John Zink Combustion Handbook. Not much of a handbook but you can beat a burner with it.


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## Gettinit

They were put out by CRC Press edited by Charles Baukal Jr.


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## rjbphd

Gettinit said:


> Industrial burners handbook and The John Sink Combustion Handbook. Not much of a handbook but you can beat a burner with it.


 Those are big boys' books!


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## Gettinit

rjbphd said:


> Those are big boys' books!


Those were some of the burners I was working on for a while. These books must have been meant for engineers entering that side of things the way the book is written. It is honestly a pretty good read. Not that easy to follow sometimes.


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## ZL700

Gettinit said:


> Those were some of the burners I was working on for a while. These books must have been meant for engineers entering that side of things the way the book is written. It is honestly a pretty good read. Not that easy to follow sometimes.


Triple duty valves (check, balance & stop) are on about all large commercial pumps. Usually requiring commisioning and balancing. 
Holohan writes books for newbies, Siegenthaler writes for professionals. Too bad few professionals read him.


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## rjbphd

ZL700 said:


> Triple duty valves (check, balance & stop) are on about all large commercial pumps. Usually requiring commisioning and balancing.
> Holohan writes books for newbies, Siegenthaler writes for professionals. Too bad few professionals read him.


 TLAOSH wasn't for newbies..


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## Gettinit

ZL700 said:


> Triple duty valves (check, balance & stop) are on about all large commercial pumps. Usually requiring commisioning and balancing.
> Holohan writes books for newbies, Siegenthaler writes for professionals. Too bad few professionals read him.


I recognize the names and have read little by Siegenthaler. They are both in the trade magazines.


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## rjbphd

Gettinit said:


> I recognize the names and have read little by Siegenthaler. They are both in the trade magazines.


 Yes, I have books by Sigenthaler and signed by him.


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## ZL700

rjbphd said:


> TLAOSH wasn't for newbies..


Steam is not for newbies

I too was taught by dead men, well ones still alive


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## rjbphd

ZL700 said:


> Steam is not for newbies
> 
> I too was taught by dead men, well ones still alive


Ur right.. its the newbies are wrecking the old steam systems


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## chuckscott

HMMM!!!


http://www.heatinghelp.com/images/attributes/743/zoom_primary_secondary_pumping_made_easy.gif


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## ZL700

rjbphd said:


> Ur right.. its the newbies are wrecking the old steam systems


More pressure! More vents!:laughing:


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## rjbphd

chuckscott said:


> HMMM!!!
> 
> http://www.heatinghelp.com/images/attributes/743/zoom_primary_secondary_pumping_made_easy.gif


 There ya go!.. now get Pumping Away....and. TLAOSH too!


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## rjbphd

ZL700 said:


> More pressure! More vents!:laughing:


 Laughing! Yeap... the main vents are leaking, plugs are cheaper than steam vents!


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## chuckscott

rjbphd said:


> There ya go!.. now get Pumping Away....and. TLAOSH too!


Just bookmarked site. Hinting around for christmas presents as I type this...:thumbsup:


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## rjbphd

chuckscott said:


> Just bookmarked site. Hinting around for christmas presents as I type this...:thumbsup:


 Add " How Come?"...


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## chuckscott

rjbphd said:


> Add " How Come?"...


I am going to add a whole lot more and a case of good beer:laughing:


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## Catlin987987

Those triple duty valves seem like a waste on a system with injection pumps. All the flow they receive is from the own pump. If it were in one large system with out injection pumps I have seen them.


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## Gettinit

Catlin987987 said:


> Those triple duty valves seem like a waste on a system with injection pumps. All the flow they receive is from the own pump. If it were in one large system with out injection pumps I have seen them.


Good point. Kinda forgot the first original post when I answered...ooops.


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