# Primary secondary piping for boilers



## Bob Rohr

Here is what I consider an ideal piping

It does use a lot of pumps, but those are cheap on e-bay.  Look for 3 speed versions.

Here are some features.

Boiler protection is easily obtained, without bang bang control.

The boiler can simultaneously provide heating and charge the buffer if the loads allow.

Additional heat sources easily connect, solar or fossil fueled, perhaps electric boiler on off peak rates, as those become more common.

Mix down temperatures could be a simple 3 way thermostatic, or a reset based control.

You can pull energy from the buffer without ever flowing through the boiler, very important.

Sorry if this ends up a double post.

hr


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## Buck1200

Could you also accomplish the same by using a small buffer tank (albeit with quite a few tappings) in place of the yellow distribution loop?  Seems like that would nix a circulator, right?  

Separate question: adding tappings to a pressurized tank would require the work of an ASME certified welder in order to remain legit.  Is that true?


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## tuolumne

H.R. - I know very little...it appears that charching the tank when no zones are calling would require pulling water through the primary loop pump.  Is it a problem to pull water through an unpowered pump?  When is the buffer's pump running?  When the boiler is cold, does the primary pump pull water through the unpowered buffer pump?  When I get my layout schematic done I'll post here to get some feedback.  Basically it is a manifold supply and return system with zone valves for the radiators and injection mixing for the radiant floor.  House gets priority, but a diverter causes extra hot water to simutaneously charge the tanks.  This primary/secondary is a new concept for me.  What if the buffer tank was in the primary loop, but zones could draw off water ahead of it if needed?  That would be simple to accomplish if it is possible to pull water through a dead pump when the house is not calling.


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## wdc1160

I like the diagram.  I wish you had inlcuded a legend for those of us who are plumbing impaired.
Do you see any potential drawbacks from this design.  2 things I would point out to you.  
1.  The method you are using to show the delta t protection needs elaboration.  If you using a mix valve-- I have never seen this method used to display it.  It also could change the scheme of the plumb, if you choose a 4 way valve- instead of 4
2.  Many member of this board believe if you choose to plumb the buffer in the way you have depicted it could be beneficial to reverse flows for a "storage phase" and "extraction phase"

These two items are personal preference and also things that 

PS I am using a very similar configuration.

What is a" bang bang control?"


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## Eric Johnson

Thanks, hot rod.


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## Nofossil

Diagrams are good. I'm trying to wrap my head around the pros and cons of having a primary loop with its own circulator. I could also use an explanation of the device symbols. By the way - what did you use to make that pretty diagram?

I thought my approach made sense, but it's a bit different. Here's what I'm doing:

I essentially have a hot (supply) manifold and a cold (return) manifold that are shared by all heat sources and heat loads. 

Each heat source has a circ that draws from the return manifold. Heated water goes to the supply manifold. 

Each heat load has a zone valve that allows water to flow from the supply through the load to the return.

When I add a radiant zone that needs cooler water, I plan on an additional circ and mixing valve for that zone as in your diagram. It will still be connected between the shared supply and return just like the other zones.

So - pros and cons. Since I'm too cheap to buy a high-capacity mixing valve, I'm doing the bang-bang thing with a zone valve for input protection. I could add a mixing valve without changing anything else, though. I think one advantage of my scheme is that it has very nearly the irreducible minimum number of components. I could eliminate a circ by plumbing my heat sources in series, but I like to have each device plumbed so that it can be isolated independently.

I've seen the loop approach many times, so I assume there's a benefit that justifies the extra circ(s). What am I missing?


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## solarguy

if you chose to install a primary/secondary piping configuration you are better off to use zone valves for your zoning needs instead of circulators. You will still have the primary circulator on your loop, the circulator on your wood boiler. The theory behind this statement is as follows:
When you look at a pump curve, most small wet rotor circulators (Taco 007) will pump up to 
14 gallons per minute depending on the head. Most of the heat zones in an average home have less than a 20,000 btu heat loss which equates to 2 gallons a minute of flow. 1 gallon per minute @ 180 degress= 10,000 btus at a 20 degree delta. When you zone w/ circulators you could be pushing 5 times that water thru the loop than you actually need which results in more fuel consumption.

Plumbers zone with circulators, heat men zone w/ zone valves


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## Bob Rohr

Great comments and quotes.  there are plenty of way to pipe these systems.  all have pros and cons.

A tank as the primary loop is an excellent option.  it can act as the air purger, primary loop, and ad some “capacitence” to your system..I agree a certified welder might be the best way to modify a pressurized vessel.

The primary loop pump needs to run for anything to happen really.  None of the secondary loops will “communicate” without that loop circ spinning.

The boiler return protection in this example is accomplished by a variable speed circulator.  As the boiler temperature rises the circ spins faster.  as it hits 140f or lower it would slow enough to allow the boiler to catch up.  A lot less component cycling.

Bang/ bang is a control the switches on off on off to provide control.  variable speed eliminates cycling of components and better temperature regulation.  The boiler output matches the flow through it with variable speed pumps.  Just like the fans on the EKO and others that have variable speed controls.

Any type of mixing valve uses pump energy.  If in fact we are chasing the ultimate use of energy, be it wood or electrical, then design around the smallest possible circ pumps.  the new ECM circulators hitting the market use about 40% less energy to get the job done.

Nofossil has a good drawing.  sometimes the pump will run at the top of it’s curve, sometimes off the bottom, and possibly right in the sweet spot.  that is one problem with a single pump that sees various loads.  if you size it to handle any or all loads together, when one small load calls it will be overpumping,  inefficient, etc.  A pressure activated bypass could help keep the pump on curve, but it also consumes pump energy.

As drawn it would be hard to balance flow through high head zones and the wide open zones.  The circuit with the least resistence will get most of the flow. Circuit setters could help, but overly complicate the system.

Primary secondary systems need circs to work properly.  you could add zone valves down stream of the circs for additional zones.  There are a lot of small circs on the market, as well as 3 speed to dial in an almost exact flow rate at very small wire to water consumptions.  we may even see a 1 watt pump on the market soon.  laing also builds some very small flow circs.

Hope this helps, it’s fun seeing and hearing of all the variations out there.  The perfect one still eludes me, but the chase sure is fun..

The drawings were done in John Sigenthalers HydroniCAD program.  a great hydronic specific program.  I'll label better next time.

 hr


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## wdc1160

You had like 100 questions to answer.  Enough that this became a sticky link instead of a thread.   

I think that some of your solutions are unique.  I am sure it is the first time I have seen some of the solutions you have posited.

As an example I don't think I have seen someone choose a variable speed circ in leu of a mixing valve.  

In a previous thread we beat to death mixing valves and the reason for having them, I have no first hand experience failure from not using them,  but try not to expereience alot of things people warn me about.

So I will pass the warning to you,  apparently low inlet temps can be real bad, be careful.  

My strategy(still brewing) for gasification is going to be mixing valve centeric ie I want to control the mix temp and flow 100%  
I think that can also be an efficient use of wood vs pump energy. 

I am still at the drawing board.

Thank Bill


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## solarguy

>Primary secondary systems need circs to work properly.  you could add zone valves down >stream of the circs for additional zones. 


Sorry Master, that is not a true statement. All you need is the primary circulator sized correctly for the load on the zones at peak demand. 

I say this based upon 35 years of hydronic experience.......


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## Nofossil

> Nofossil has a good drawing.  sometimes the pump will run at the top of it’s curve, sometimes off the bottom, and possibly right in the sweet spot.  that is one problem with a single pump that sees various loads.  if you size it to handle any or all loads together, when one small load calls it will be overpumping, inefficient, etc.  A pressure activated bypass could help keep the pump on curve, but it also consumes pump energy.
> 
> As drawn it would be hard to balance flow through high head zones and the wide open zones.  The circuit with the least resistence will get most of the flow. Circuit setters could help, but overly complicate the system.



Thanks for the detailed response. If I understand you correctly, the benefits of the primary / secondary approach are that the load on the pumps is more constant and the zones are easier to balance.

I hadn't thought of either of those as problems. Here's my understanding. Please clarify if I don't quite have it right, and please excuse my insistent questioning. I'm trying to walk a fine line between learning and arguing, hopefully on the right side most of the time ;-)

A circulator has a pressure / flow curve such that the less resistance, the more flow. This compensates to some degree for the varying number of zone valves that might be open - more zones, more flow. Manufacturers strive to make this curve as linear as possible, so that you will get close to twice the flow with two zone valves open as with one.

Zone valves have a very small orifice so that the valve itself makes up a significant percentage of the head loss for each zone. In that way, the zones are close to balanced. There are no 'wide open' zones. Any zone that gets more flow will simply reach temp sooner and shut off.

The circulator will pump less with fewer zones open, which will have the effect of increasing the boiler temp due to less flow. Wouldn't a variable speed pump increase its speed under those conditions, making it work even harder than the single speed? Does power consumption vary significantly with head loss? How would you define 'sweet spot' for a given circulator?

Finally, I haven't seen a variable speed pump that's less than $300, even on eBay. The ECM pumps look to be in the $400-$500 range unless there are sources I haven't found. Would it be too much to ask you for rough-order-of-magnitude prices that folks could expect to pay for the more esoteric components? I've shied away from some approaches because of perceived cost. Love to find out I was wrong.

For mine:
Circ pumps: Taco 007IFC or Grundfos UPS15-58FC - about $50 on eBay, $75-100 in the real world
Zone Valves: Honeywell Zone Valves - about $60 on eBay, about $80 in the real world
3/4 Mixing valves (DHW): Honeywell AM101-1-C - about $50 on eBay


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## slowzuki

In a primary-secondary what he is saying is true, and what you say is true if you don't have any load shedding.  He is talking about zone valves downstream on zones off the loop, not zone valves in the loop.



			
				solarguy said:
			
		

> >Primary secondary systems need circs to work properly.  you could add zone valves down >stream of the circs for additional zones.
> 
> 
> Sorry Master, that is not a true statement. All you need is the primary circulator sized correctly for the load on the zones at peak demand.
> 
> I say this based upon 35 years of hydronic experience.......


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## Bob Rohr

In order to have a true primary secondary circuit you need closely spaced tees for the supply and return.  properly installed there will be no flow to those secondary branches with just the primary loop pump running.  That is the design intent of primary secondary piping.  For some excellent reading on P/S check out Dan Holohans books "Pumping Away' and "Primary Secondary Made Easy" at heatinghelp.com.  Also John Sigenthaler has quite  few articles available at www.pmmag.com on primary secondary design and applications.

The new small wet rotor circs we see hitting the market with variable speed have several modes.

Some change there speed based on deltaP or change in pressure.  In a zone valve system as zones close off the pump, electronically, senses this and reduces it's rpms accordingly.  i have a 3 zone system in my shop and the circ runs from 17- 38 watts based on which zones are open.

They can also work as a delta t or temperature difference mode.  the Grundfos MixiMiser comes with two sensors.  the control on the pump watches the two sensors and increases or decreases it's speed accordingly.

I believe the new Wilo Stratos has the ability to work in either mode.

Yeah, they are more $$ but with all the features and reduced power consumption I expect they will start showing up on more systems. Ii suspect price will drop as more manufacturers off this technology.

Most pumps run most efficiently in the middle third of their pump curve.  When you size a circ pick one that will operate your system in that middle range for best wire to water efficiency.

 hr


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## wdc1160

I will second nofo's statement.

One of the things that is lost on the underinformed plumbers here are that we don't know enough to quantify how much wood,electric, material cost your saving us.


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## slowzuki

The last thing I will note is that a variable speed drive used instead of correctly sizing the pump is less efficient for fixed loads.


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## solarguy

aw, come on, I'm not an uninformed plumber.

I agree with the 2 closely spaced tees. The intent is to create hydraulic jump to prevent the primary pump from pushing water thru the shell of the boiler or thru your zones if your zoning w/ circulators. The balance of your tees for your supplies & returns do not have to be closely spaced if you're zoning w/ zone valves. The only time we zone w/ circulators is for radiant manifolds, everything else gets zoned w/ zone valves. By doing this we feel we have better control to balance out the system for the proper gpm thru a zone.

Everyone has an opinion on what method is best, it all boils down to whatever you feel the most comfortable in doing or whatever lifts your skirt.


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## Eric Johnson

Sorry, but no men wearing skirts allowed in the Boiler Room.

Cussing and spitting on the floor is one thing, but the skirt business is where I draw the line.


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## Gooserider

Eric Johnson said:
			
		

> *Sorry, but no men wearing skirts allowed in the Boiler Room.*
> 
> Cussing and spitting on the floor is one thing, but the skirt business is where I draw the line.



Aye, and as 1/4 Scotts (Paternal Grandmother was a MacKenzie), (or more if the Scapa is flowing) I must ask what ye has against skirts?   %-P 

Gooserider


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## Eric Johnson

They're only permitted when accompanied by bagpipes or when worn by Mel Gibson. Of course, anyone carrying a bottle of fine Highland scotch gets in no matter what they're wearing (or not wearing).


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## Green DIY Guy

The layout looks like there might be one un needed pump


If I understand what I have been told you might be able to eliminate a pump and possibly consider placing the primary circulator on the supply going out, unless it's a heat issue with a wood boiler. I found great advice and plenty of layout examples here http://www.houseneeds.com/shop/heatingproducts/heatu/heatinguniversity.asp?stype=../../products.htm
they answered my questions and help set up a "light weight " system using 3 speed pumps. Simple is better and extra pumps means more elec :O(


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## Tony H

Forest thanks for the link now I can read and learn so my input can be more than ........... What do you think of my new plumbing company 
Plumbers in skirts ( an all female crew) I think we might do quite well !


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## Gooserider

Tony H said:
			
		

> Forest thanks for the link now I can read and learn so my input can be more than ........... What do you think of my new plumbing company
> Plumbers in skirts ( an all female crew) I think we might do quite well !



Sounds good to me - a good way to make "Plumbers Butt" a non-problem (much to the dissappointment of Duluth Trading Co.) ;-P 

Gooserider


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## steam man

I thought this might be a good place to put this link. I also thought I had a good piping plan ready to go until this publication made me think. I would be interested in hearing from anyone that has used this hydraulic separator system.  

http://www.caleffi.us/caleffi/en_US...gazine_detail_0000054/type/magazine/index.sdo


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## SteveJ

hot rod,

Thanks for the great post...

How do you "pull energy from the buffer without ever flowing through the boiler"? In the diagram, the piping looks to be configured to only charge the buffer. How do you pull through the pump with the check valve?

Please tell me what I am missing,
Steve


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## heaterman

SteveJ said:
			
		

> hot rod,
> 
> Thanks for the great post...
> 
> How do you "pull energy from the buffer without ever flowing through the boiler"? In the diagram, the piping looks to be configured to only charge the buffer. How do you pull through the pump with the check valve?
> 
> Please tell me what I am missing,
> Steve



The Primary loop is the common denominator in the piping. The boiler itself is a secondary loop. Therefore, you can set up your control strategy to pick up heat from the highest temperature source. If the boiler would happen to be at a lower temp than the tank, the boiler circ would stop and the tank circ would come on dumping its heat into the primary loop.


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## SteveJ

So, there should be two circuits into the butffer tank:

1. As drawn in the diagram, to charge the tank from the primary loop.
2. (Not shown in diagram) Circulator reversed from that in diagram with a short dip tube, to extract heat from the tank to the primary loop.

Correct?

Then what is the general rule for sizing the primary circulator in relation to the secondary circulators?

Thanks,
Steve


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## Bob Rohr

Sure, you could have two loops into the buffer.  What I find is any time my boiler exceeds 150 the buffer circ is running.  As such the tank is always blended, not much stratification with the buffer tank circ running. 

On one hand I want the cooler water from the bottom of the tank to return to the primary loop and boiler to leverage delta t to the boiler and keep the efficiency up.

However if the tank stratifies, for instance over night without the buffer circ running, in that case you would want to pull any heat loads off the top, warmest point.  My buffer circ runs until that tank drops to 100F as my radiant floors can use temperature that low.

If you have loads thay require higher temperatures, of course shut down the buffer at the lowest  possible "useable" temperature.

Whenever the buffer circ is off the boiler output would be going directly to the loads without "seeing" the buffer.

Keep in mind under "ideal" conditions, at load, the boiler would be matched exactly to the load and the buffer becomes "unknown" to the system.  The buffer is merely a parking space, either for excess btus, over heat protection, maybe solar storage input.

You might consider the buffer as a "fixer" for the in-ability of solid fueled appliances to track close or exactly to the load.  Different jobs require different size tanks to try to "nail" the perfect blend of not storing anymore then really needed, but enough to buffer all conditions, or perhaps offer some "non burn" times

I can't say there is an ideal piping, size, or control configuration.  It really needs to be sized and designed to the task you have in mind.  I chose 500 gallons because it will buy me a days worth of heat, at design.  It fit in the space nicely, and I don't mind switching to a mod con LP boiler back up.

Others here want to burn hard and long and store more "time."  For them more capacity may be better.

Keep in mind more capacity = more standby loss. I feel there is an upper limit to realistic thermal storage, but it's a moving target 

Th primary loop circ is usually a low head, high GPM circ. It's ONLY lob it to move fluid around that circulator loop.  It doesn't move any flow through secondary loops.  Either the Grundfos 15-58 or Taco oo7 on speed 1 will usually be fine for that.  To move 150,000 BTU at a 20Fdegree delta T you need to move 15 gpm.  look for a circ to do that job at a low head,  some of the DHW recirc pumps are great, but expensive as they are usually bronze or stainless volutes. 

 hr


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## SteveJ

master of sparks,

Thanks for the detailed explanation...

For a strictly off-grid house with power consumption at a premium, I think I like nofossil's approach over the primary/secondary approach. In nofossil's setup there is never more than one circulator on at a time and maybe a few zone values. With the primary/secondary setup, it appears that the primary pump is on 24/7 and there seams to be the same number of zone valves required and more circulators = more power consumption.

Am I comparing apples to apples? 

What do you think is the ultimate off-grid setup?

Thanks,
Steve


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## Bob Rohr

these off grid friends, Larry and Suzanne in northern California used greenhouse window operators connected to spring loaded ball valves to control the temperature of his gravity fed radiant wall heating system. 

 Solar via PV powered circs to supply the wall radiant and DHW. Zero power consumption for heat and DHW.  Very clever, and comfortable from a few years of experience.  Small, about 1KW of PV power.  They do have a back up generator with a homemade HX for heating the solar tank when it runs.

 hr


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## heaterman

steam man said:
			
		

> I thought this might be a good place to put this link. I also thought I had a good piping plan ready to go until this publication made me think. I would be interested in hearing from anyone that has used this hydraulic separator system.
> 
> http://www.caleffi.us/caleffi/en_US...gazine_detail_0000054/type/magazine/index.sdo



RE: Callefi

Here's a project we did last year in a church. The hydraulic separator is the green and silver tank looking affair in the middle of all the pipes. We used this method of piping because flow requirements for the system are far different than the boilers that drive it.


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## Eric Johnson

Nice looking job. Is that an expansion tank on the top?


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## heaterman

Eric Johnson said:
			
		

> Nice looking job. Is that an expansion tank on the top?



Yes it is. The old tank was more than adequate in capacity due to removing a 1,400 pound cast iron monster and replacing it with a couple small modulating condensers. Probably 40-50 gallons less system capacity now. It was an interesting job because all the old boys in the church were simply dumbfounded that those two dinky wall hung boilers were capable of heating 8,500 sq ft. They literally hovered in the boiler room while we were working and loudly proclaimed their disbelief. After this winter with a nice warm church and a 40%+ reduction in their fuel use.........let's just say that there was a conversion of a non-spiritual type going on there.


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## BrownianHeatingTech

heaterman said:
			
		

> Eric Johnson said:
> 
> 
> 
> 
> Nice looking job. Is that an expansion tank on the top?
> 
> 
> 
> 
> Yes it is. The old tank was more than adequate in capacity due to removing a 1,400 pound cast iron monster and replacing it with a couple small modulating condensers. Probably 40-50 gallons less system capacity now. It was an interesting job because all the old boys in the church were simply dumbfounded that those two dinky wall hung boilers were capable of heating 8,500 sq ft. They literally hovered in the boiler room while we were working and loudly proclaimed their disbelief. After this winter with a nice warm church and a 40%+ reduction in their fuel use.........let's just say that there was a conversion of a non-spiritual type going on there.
Click to expand...


If that a structural caulking tube up top? 

Joe


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## heaterman

If that a structural caulking tube up top? smile

Joe 

Yep. It's what we use to glue the boilers to the wall


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## zadwit

Duplicate trimmed....  Gooserider


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## zadwit

I have an EKO-60 supplying 2 five hundred gallon propane tanks set side by side. My primary heat is currently a Burnham V-15 boiler (135, 000 BTU) feeding two radiant floor zones and one small base board radiator zone. 
I plan on running 1-1/2" pipe, galv. or copper from the EKO-60  to the propane tanks and return to the EKO-60 with same size pipe. There will be a small primary loop with a Danfos Tee to assure return water temp. Then I plan on "tee ing" off from the top of the propane tanks (where the hot water enters) and going to the Burnham boiler. I will need to install a flat palte heat exchanger between the propane tanks and the burnham boiler since the burnham side has glycol. We have to use glycol up here in North Pole, Alaska in case the power goes off or the system fails. It would cost too much to fill the propane tanks with 1000 gallons of glycol, so will use water.
Some one told me to install two closely spaced "T's" on the inlet(return water) side of the burnham oil fired boiler. THis way, when the zones call for heat, the burnham circulator sucks the hot water thru the oil boiler to the zones. When the zones are not calling for heat, the hot water from the tanks circulates around the heat exchnager between the heat exchanger and the oil boiler(2  "Ts"). It seems to me that I need to connect the two circ pumps,( the ones that pump water from the tanks to the hx and from the hx to the oil boiler), to the same control that runs the oil boiler circ pumps. This means the honeywell aquastat on the  oil boiler would have to power up 4 circ pumps. Is this too much? Do I need a switching relay?
The EKO-60 has a large circ pump, grundfos UPS 26-99FC. I think it runs when the EKO-60 controller decides it needs to run.
Does anyone see any major flaws with this setup? I am real close to plumbing this all in.
Thanks in advance,


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## Bob Rohr

frozenasset said:
			
		

> I have an EKO-60 supplying 2 five hundred gallon propane tanks set side by side. My primary heat is currently a Burnham V-15 boiler (135, 000 BTU) feeding two radiant floor zones and one small base board radiator zone.
> I plan on running 1-1/2" pipe, galv. or copper from the EKO-60  to the propane tanks and return to the EKO-60 with same size pipe. There will be a small primary loop with a Danfos Tee to assure return water temp. Then I plan on "tee ing" off from the top of the propane tanks (where the hot water enters) and going to the Burnham boiler. I will need to install a flat palte heat exchanger between the propane tanks and the burnham boiler since the burnham side has glycol. We have to use glycol up here in North Pole, Alaska in case the power goes off or the system fails. It would cost too much to fill the propane tanks with 1000 gallons of glycol, so will use water.
> Some one told me to install two closely spaced "T's" on the inlet(return water) side of the burnham oil fired boiler. THis way, when the zones call for heat, the burnham circulator sucks the hot water thru the oil boiler to the zones. When the zones are not calling for heat, the hot water from the tanks circulates around the heat exchnager between the heat exchanger and the oil boiler(2  "Ts"). It seems to me that I need to connect the two circ pumps,( the ones that pump water from the tanks to the hx and from the hx to the oil boiler), to the same control that runs the oil boiler circ pumps. This means the honeywell aquastat on the  oil boiler would have to power up 4 circ pumps. Is this too much? Do I need a switching relay?
> The EKO-60 has a large circ pump, grundfos UPS 26-99FC. I think it runs when the EKO-60 controller decides it needs to run.
> Does anyone see any major flaws with this setup? I am real close to plumbing this all in.
> Thanks in advance,



I don't think so... but without seeing a drawing??

Ideally a parallel, if not a true P/S as shown.  As drawn here you would like to go directly from either boiler to the load.  Without passing through storage or the unfired boiler.  In your example (lower left drawing I think?) the oil boiler would need to be circulating for closely spaced tees to work.  Not ideal in my mind, unless a tankless coil is used for dhw.

Here are a couple rough drawings, although an additional 3 way zone valve could select from EKO or storage for a source.  It gets to be a bit of piping work to cover all of your bases under any combination of 'players".

 hr


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## zadwit

I do have a DHW coil inside the Burnham oil fired boiler. I will try to attach a picture of a dwg. that was suggested to me as one way to plumb this all in. The hot water would leave the EKO and go to the storage tanks.A large "T" in the top of the storage tank would allow hot water to to be pulled from (A) the tank or(B) the EKO if it is producing hot water, to the flat plate heat exchanger. From the heat exchanger it would supply hot water to the return or inlet side of the oil fired boiler if and only if the oil boiler circulator is running sucking in hot water. Does this make sense? I realize it will not help much for domestic hot water. I could buy and install a superstor.
1) Do I need to have another 1-1/2" female fitting in the storage tank, right next to where the hot water enters the tank, or will it work to install a large "T" so that hot water from the EKO can go either into the tank or directly to the hx?
2)Should I install an aquastat on the storage tank so that it will "open" when the tanks cool down so that the circulator will not heat the tanks from the oil boiler?
3)What do you think? Will this work?
Thanks, Mark


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## zadwit

Which is a better  location for a danfos valve to maintain warm water return to the boiler? On the return side of the EKO-60 or on the supply side? I've seen both drawings.
Thanks, Mark


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## mouchey

I have a question?  I am installing a dual fuel system with primary and 2ndary loop.  I have an EKO 25 and a Munchkin condensing boiler with superstore indirect water tank.  I am trying a 500gal propane tank for storage.  Here's my concern is getting hot water from this storage tank makes me nervous.  Does anyone have a recommendation of how to pipe a zone for the indirect water tank off the fossil fuel boiler so as not to use this storage tank water to wash or clean dishes?  I have read a lot online here from NoFossil and others would love to know what you all think would really work.  I am ready to do this install next week. 
Thanks,
MJ


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## Nofossil

Boiler and storage tank water is not potable water. Use an indirect tank (Superstor or equivalent) and/or heat exchangers to keep them separate.


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## Gooserider

What Nofossil said, with one minor possible exception - 

There is an outfit called Radiantec that does a radiant heating system that is primarily solar and gas DHW heater based, but can be used w/ a wood boiler & storage setup.  Their system pulls supply water into the radiant plumbing, and gets DHW through it.  The claim is that this gives greater efficiency by preheating the incoming water in the system before it gets to the main heat inputs, and also a small amount of "radiant cooling" in the off season.

They claim to be fully approved by all the major plumbing codes, but it seems that Mass. is behind the times so I couldn't do their setup    but it sounds good.  They also have more conventional setups which I could use, and I've been considering them a little bit as their pricing looks pretty good...

Not sure how they are reputation wise.

Gooserider


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## pybyr

I'm sold on building my system around the primary/ secondary layout-- but some questions--

first- so that I can draw some things up for feedback from you all, what's a good "HVAC diagram drawing for dummies" program, preferably one that's free and that'll run on either an Intel Mac or an ancient 33mHz pentium laptop

second- are any of you familiar with TACO "twin tees":

http://www.taco-hvac.com/en/products/LoadMatch<sup>®<_sup>+Twin-Tee<sup>®<_sup>+Fittings/products.html?current_category=118
and
http://www.taco-hvac.com/en/products/LoadMatch<sup>®<_sup>+Twin-Tee<sup>®<_sup>+Fittings/track_file.html?file_to_download_id=15084

they look like an ingenious way to achieve the same effect as "closely spaced tees" only with less horizontal real estate in & occupied by the primary loop.  Anyone aware of any drawbacks?


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## kabbott

I don't no what software the experts use but I have played around with taco HSS.

http://www.taco-hvac.com/en/products/ Taco Hydronic System Solution® (HSS)/products.html?current_category=84

It will show head loss and auto select pump size and such and also has the twin tee's.
many different types of emitters and buffer/storage tanks.

edit::Hmmmm link didn't work, copy and paste.


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## babalugatz

Gooserider said:
			
		

> What Nofossil said, with one minor possible exception -
> 
> There is an outfit called Radiantec that does a radiant heating system that is primarily solar and gas DHW heater based, but can be used w/ a wood boiler & storage setup.  Their system pulls supply water into the radiant plumbing, and gets DHW through it.  The claim is that this gives greater efficiency by preheating the incoming water in the system before it gets to the main heat inputs, and also a small amount of "radiant cooling" in the off season.
> 
> They claim to be fully approved by all the major plumbing codes, but it seems that Mass. is behind the times so I couldn't do their setup    but it sounds good.  They also have more conventional setups which I could use, and I've been considering them a little bit as their pricing looks pretty good...
> 
> Not sure how they are reputation wise.
> 
> Gooserider





We installed a Radiantec system for a customer (upon her insistence & she supplied the product= NEVER an ideal situation for an installer). It uses potable hot water from a Polaris 75 gal. gas-fired/sealed comb. American Water Heater (95% eff they claim) & they recommend 3/4" pex tubing= a big pain-in-the-ass during install w/ kinking (it is a thinner walled tubing) & overkill as well.
I'm not a big fan of this system in that there exists the possibility of stagnant water in some of the longer loops during warm months, when circ. pump(s) are off. They claim water will flow through all of the loops whenever there is a demand for hot water, but as we all know, no installation is going to be perfectly balanced. There are going to be loops with more tubing than others, and water is going to seek path of least resistance. Legionnaire's anyone? Too risky without installing a timer on all circ. pumps to operate them during off season...or Taco VS pumps that cycle every 3 days during non-use....


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## Gooserider

Thanks for the comments babalugatz...  I'm not in a big rush on it, but I would love to do a solar house heat / DHW / pool heating setup at some point...  I think we have an ideal setup for some sort of solar - (12/12 pitch roof, south facing, not to much shade, etc.) and I don't see solar electric being cost effective any time soon.  However I could definitely put up a big water heating array, and (I think) take on a big chunk of the heating load...  Not sure it would be worth trying to do a boiler as well, would probably want to do the system on pure solar for a while to see how it handled it...

Now, according to Radiantec, they meet all the major codes, for whatever that's worth...   It would be nice to believe that they have satisfied all the official types that there isn't any increased risk, no matter how unbalanced things are...   However the combined system is not allowed under current Mass. codes so that isn't an option.  I could do a heat-exchanger setup with the storage tank which would presumably cost me some efficiency for the extra pump, but would work pretty well I think. 

What do you think of that Polaris hot water heater?  Our current conventional style (Rheem) natural gas water heater is presumably approaching end of life based on installation date, so I'm guessing we'll be needing to replace it within the next few years regardless....  I don't like some of what I've heard about tankless heaters, but a high efficiency condensing water heater sounds like a good deal - high efficiency, avoids the quirks and mechanical issues with tankless jobs, less of a safety issue than a conventional, etc...

As to the tubing - I suspect that 2/3 of the house could be done with fairly small tubing, but that our living room which has a fairly small floor area, but has an essentially 2.5 stories tall cathedral ceiling (24' center height, and 3 BIG picture windows (2 at 6'x6' and a 6' half round) will need all the help it can get - our house is pretty, but not practical...

Gooserider


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## LeonMSPT

New oil fired hot water baseboard system is up and running great. Contractor left two valved T's at supply and return, and will be coming with the wood/coal boiler sometime in the next couple of weeks. He left a T'd valve at the supply and return on the boiler, and is going to pipe the wood/coal with 1 and 1/4 inch steel pipe with a circulator, air trap, and expansion tank. Says this way, the boiler remains hot at all times, better for it, and it give me some heat storage as well. Didn't have money for a "gassifier" and he wasn't sold on them anyway, without heat storage at least. 

Anyone used a set-up like this? Problems? 

Thanks in advance.


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## joemeintzer

buck1200 said:
			
		

> Could you also accomplish the same by using a small buffer tank (albeit with quite a few tappings) in place of the yellow distribution loop?  Seems like that would nix a circulator, right?
> 
> Separate question: adding tappings to a pressurized tank would require the work of an ASME certified welder in order to remain legit.  Is that true?



Yes that is absolutely true if you're concerned about that type of thing.  That work would fall under a pressure vessel code or power piping ASME B31.1 I wouldn't be overly concerned if you're doing it on your own equipment though I'll bet the warranty would be broken anyway.


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## jimmie ray

solarguy said:
			
		

> if you chose to install a primary/secondary piping configuration you are better off to use zone valves for your zoning needs instead of circulators. You will still have the primary circulator on your loop, the circulator on your wood boiler. The theory behind this statement is as follows:
> When you look at a pump curve, most small wet rotor circulators (Taco 007) will pump up to
> 14 gallons per minute depending on the head. Most of the heat zones in an average home have less than a 20,000 btu heat loss which equates to 2 gallons a minute of flow. 1 gallon per minute @ 180 degress= 10,000 btus at a 20 degree delta. When you zone w/ circulators you could be pushing 5 times that water thru the loop than you actually need which results in more fuel consumption.
> 
> Plumbers zone with circulators, heat men zone w/ zone valves



I think you could have too high a flow rate with a zone valve system, when only one zone is calling, and you sized the single pump for the capacity of all the zones - it becomes oversized for that one zone?
But the most important reason to utilize pump zoning is that in the event of a pump failure, you still get heat to the other zones with the properly working pumps. That will keep the occupants happy until the pump is replaced, and hopefully even prevent frozen and burst pipes during severe cold conditions.


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## heaterman

jimmie ray said:
			
		

> solarguy said:
> 
> 
> 
> 
> if you chose to install a primary/secondary piping configuration you are better off to use zone valves for your zoning needs instead of circulators. You will still have the primary circulator on your loop, the circulator on your wood boiler. The theory behind this statement is as follows:
> When you look at a pump curve, most small wet rotor circulators (Taco 007) will pump up to
> 14 gallons per minute depending on the head. Most of the heat zones in an average home have less than a 20,000 btu heat loss which equates to 2 gallons a minute of flow. 1 gallon per minute @ 180 degress= 10,000 btus at a 20 degree delta. When you zone w/ circulators you could be pushing 5 times that water thru the loop than you actually need which results in more fuel consumption.
> 
> Plumbers zone with circulators, heat men zone w/ zone valves
> 
> 
> 
> 
> I think you could have too high a flow rate with a zone valve system, when only one zone is calling, and you sized the single pump for the capacity of all the zones - it becomes oversized for that one zone?
> But the most important reason to utilize pump zoning is that in the event of a pump failure, you still get heat to the other zones with the properly working pumps. That will keep the occupants happy until the pump is replaced, and hopefully even prevent frozen and burst pipes during severe cold conditions.
Click to expand...


You are absolutely correct. When a circ is sized to provide required flow to all zones simultaneously (design conditions) it stands to reason that flow will excessive when only one zone is calling. This can be solved in a couple ways. The first being to install a pressure differential bypass valve and bleed the excess energy created by the circ back into the return or by a far more preferable method which uses a variable speed circ that ramps up and down according to the load.

Also very true is that a multiple circ system provides you with redundancy not achievable with zone valves.


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## thehaas

LeonMSPT said:
			
		

> New oil fired hot water baseboard system is up and running great. Contractor left two valved T's at supply and return, and will be coming with the wood/coal boiler sometime in the next couple of weeks. He left a T'd valve at the supply and return on the boiler, and is going to pipe the wood/coal with 1 and 1/4 inch steel pipe with a circulator, air trap, and expansion tank. Says this way, the boiler remains hot at all times, better for it, and it give me some heat storage as well. Didn't have money for a "gassifier" and he wasn't sold on them anyway, without heat storage at least.
> 
> Anyone used a set-up like this? Problems?
> 
> Thanks in advance.


  i have a d.s.machine coal wood boiler.i had oil boiler that i tied in totalked to lot of people asked plumber got million answers and many plumbers not interested in installto much work for them and area they never do.basically they want boiler with all controlls on it ready to wire to 120 then hook up oil lines takes them about 8 hours and they make 1500 to 1000.so i hooked up my self running about 2 years plumbed it series circuit not put 3 inch and quarter valves in oil fired boiler return line shut middle one off open two outers so flow is .out of top wood boiler down to oil boiler up threw oil boiler out to base board back down to return into bottom of wood boiler.when i dont use wood boiler i close outer valves on return line open middle valve shutting off water flow to wood boiler.i think i got valve idea from alternate heating web site.my dump zone is separate zone ran threw old cast iron radiators boiler holds 85 gal radiators are half capacity around 40 gal.dump zone has its own circulator thats turned on by aquistat switch on top off wood boiler also has its own zone valve also has another one thats normally closed until power failure the it gravity flows.all controlls are taco boxes have step down transformer built in hot water tank connections called prority zone that means when hot water calls for heat heat zone are turned off till hot water up to temp no shortage of hot water.my buddys electrician and helped wire.taco controll boxes really make install easier.4 wire zone valves 2 wires for opening motor off valve ,other to wires are end switch that turns circulater on ,all locations for wires are labeled inside box real easy.other controll box is for dump zone aquastat switch on top of wood boiler turns on controll box that opens dump zone valve and turns on circulater.originally i hooked up wood boiler parralel to oil boiler return to return out put on top hooked to oil out put did not work correct wood boiler temp around 190 oil boiler around 140 more water was circulating threw oil than wood boiler.all electrical on original oil boiler is factory no changes.have stainless steel type a chimney heats up quicker better draft easier cleaning.had in block chimney low draft creosole build up plus that red clay liners are junk and coal fumes detroy in no time,had many discussions with people about chimneys they are good for oil or nat gas ormaybe old fire place,not for coal chimney run around 2000 block chimney aruond 2500 with in stall ,plus ss goes up lot faster.basically no contracter wants to work unless he can make 1500 a day on project or min 500 a day,they all cry about being broke but dont want to work unless they can hit it big on you.i work on cars hourly rate is 40 dollars hour when contracters come to us they sure dont want to pay talk about cheap drunks.so when hooking these thing up your on your own unlee you want to pay like 10000 intall.any question e mail me i dont mind giving advice mine is up and running great ,best way to learn is make mistakes and learn from them ,you could draw all diagrams plan out then start and everything changes


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## surviverguy

Three speed circulators have lower wire to water efficiency than single speed circulators. You come out ahead calculating the headloss and needed flow rate and buying the right circulator for the job. The variable speed circulators are very efficient as well. The three speed units are mostly energy hogs.


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## ALASKAPF185

surviverguy said:


> Three speed circulators have lower wire to water efficiency than single speed circulators. You come out ahead calculating the headloss and needed flow rate and buying the right circulator for the job. The variable speed circulators are very efficient as well. The three speed units are mostly energy hogs.


 That seems to be a pretty general and broad statement for all circs. I haven't read anything about this before. A Grundfos 15-42 3 speed is well under 100 watts at medium its only 54 watts for an example.
Some standard piping designs, these are from the caleffi idronic's edition on wood boilers. We have always drawn the load from the buffer tank and the boiler only heats up the battery, unless there are multiple types of boilers or an IDWH. This way the buffer tank or storage acts like a hydraulic separator/air removal/dirt separator all in 1. Thus no need for a "primary loop" and primary pump. When sizing a primary loop circ, when a design calls for one, the pump is sized for 2 feet per second as the idea is to keep the primary loop very low head loss so the secondary circuits are hydraulically invisible to each other.


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## Trex83

ALASKAPF185 said:


> View attachment 63923


Thanks Alaska. Now my mind is at peace from all these P/S discussion. Doing it the European way with water storage seems simpler in me and my dads mind. Setting up like Figure 7.1 this summer. We used a piping design from Switzerland. The only difference is that the loop to the house is drawn off the first tank and the garage is drawn of the second tank. The radiant floor to the garage doesn't need to be as hot as what is going to the house.
trex


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