Help Me Grasp This

CMadatMe

Ok. I  think I'm having a dumb attack today but then again maybe not.

Attached are the pump curves for Taco 00 circs, more importantly a 0011 for this discussion, the tech data manual for Vitodens 200 and the boiler we are discussing is a WB2B-80. Page 10  Fig 13 of the TDM has the boiler pressure drops at given gpms. Page 13 provides the recommended boiler pumps at given flow rates, head and delta-t.

Anyone have ideas as to where the 0011 will operate on its curve? Since the 0011 curve is similar the the UPS26-99 on Speed 3 I could assume the 25 delta across the boiler but want to make sure I'm going to be able to pull out the gpm needed as we get into design days.

I know everyone is going to take the same path as me. Just put in the recommended pump but the question of the day is, where will the 0011 operate, what will it give me for gpm? What delta should I expect to see across the boiler? What efficiences am I giving up by not running a 40 degree delta-t across the boiler?

STEVEusaPA

quite confusing, I agree...

I read everything you posted, twice.

I would go with the UPS26-99 on speed 3, you can always change it to 2. It appears to me the 0011 would do about 20 gpm @ 13 feet of head with a 25 delta t.  But whatever the numbers will be, they'll be fixed.  So I would give myself an opportunity for variations, without having to yank the circ.

Depending on where you live (it's apparently still fall in Philadelphia for another week), you could check out the grunfoss on each speed, checking delta t with thermometers, and flow rate with gauges (easy to add of course if you havent already piped it up).

On a side note, I was able to design my house, at my suppliers office, with his Wrightsoft program, and it worked almost exactly as figured, checking flow and delta t with gauges/thermometers.  When I put all the same data into a very popular (on this site) design program, the program warned me 4 of the 6 zones, the flow would be too slow.  Go figure .

I'm anxious to hear what others have to say and what you decide.  Let us know what you decided and how it worked.  Sorry I couldn't be more help

CMadatMe

No Decision

I use Grundfoss on all my Vitodens. I'm posting this to get feedback as to the performance of the 0011 and what I'm giving up. See I'm really ticked off today with a "Green Rep" who also happens to be a Viessmann rep. He had a customer call me out of spite because I changed the 0011 he quoted as a boiler pump to the proper Grundfoss pump and on start up he told the customer he doesn't do " Red Pumps" so the contractor needed to call me to tell him what speed to run it at.



I sent him an e-mail and asked him to read his TDM and the pages I posted so he could help the next contractor. II also asked him to please tell me what delta I would expect out of the 0011. Haven't received that anwser yet. I run them on Speed 2 for the 80. Want the 40 delta. What ticks me off more then anything is that he is the Viessmann rep and at the point he said he doesn't do red he stopped representing Viessmann as he should have.

NYplumber

confused

Disclaimer: I'm not at all familiar with the Viessmann boilers.



Confused to why you are shorting yourself and designing to a 25dt vs a 35 or 40.



At 25dt the 0011 will flow fine.





Explain more, looking to learn. Every day on this site is like another day at school.

CMadatMe

I'm

Not shorting myself. Always use the recommended 26-99 for a 40 delta. Trying to figure out what and where the 0011 gets me.

NYplumber

wrong wording

Wrong wording on my part.

The 0011 can do 13gpm at ~3.5ft.



What am i missing from the question?

CMadatMe

You Sure About That

That pump moves alot more water then 13gpm at 3' of head. That's the question. As flow increases head increases, where will the 0011 operate at and at what delta-t. I really think if I had to choose a taco pump it would be the 00R not the 0011.



http://www.taco-hvac.com/uploads/FileLibrary/00-3speed_family_curves.pdf

NYplumber

misunderstood

My mistake, I misunderstood what the question was.



Can you please repeat the question in laymans terms?

What are you trying to achieve? A 25dt or using a 0011 instead of a Grundfos equivalent?

with the OOr the lowest dt you can run will be 35 according to what I gather from comparing the manuals.

icesailor

Flow?

Flow increases when head increases?

The pump curves show that as head increases, flow goes down. Doesn't it?

CMadatMe

I Was

Referring to the head of the boiler not the curve of the pump. Trying to figure out where the 0011 will operate. Maybe I'm thinking too much..

NYplumber

saying

Like the saying goes, the more you know, the more you don't.

Speak to tradesmen, boiler minded pencil pushers, and handymen. For the most part they don't think into pumps, they just add one and it works. All without thinking abt dt, headloss, flow rates, etc. And all are happy (most times).



Ur question still stumps me, drawing me more curious to understanding what your after and how I can learn from this.

I'm staying tuned to this thread.

CMadatMe

Operating Point

I'm trying to figure out what gpm the 0011 is going to operate at and what delta I can expect to see across the boiler. The listed Grundfoss pumps in the tech data manual are actual flow rates those pumps are providing at those heads. We can assume the 0011 will be similar to the 25 degree delta because the pump rides just about the same curve. I want to know without assumption. My concern is not being able to move gpm as I get closer to design conditions when I need btus the most.



This pump was forced upon me and I chose not to use it instead using the proper Grundfoss that gives me the 40.

Paul Pollets

Which pump?

Is this a system pump or the pump between the boiler and LLH?

CMadatMe

Boiler Pump

We are talking about the boiler pump.

scott markle_2

15 gpm@ 5 ft. of head

the 0011 is too big, it's not going to exceed the 35 gallon limit, but it going to move more water than required. Most guys are still in the giononi mind set of pump baby pump, the Vito can thrive on high deltas, why waste electricity and run low deltas if we don't have to,

I would be shooting for 15-18 gpm, my read of the curve says the 0011 generates more head than required at this flow, thus more flow than desired



I think your question is how many gpm will the 0011 move through the boiler in question, simple answer - too many for the delta you want. but if someone can explain how to use the pump and boiler info provided to determin the actual flow that will result, I could use a refresher.

CMadatMe

Hey Scott

I agree with you. I'm on a war path to figure it out. Next time we talk I'll fill you in. In short, read my post after the intial post.

scott markle_2

Variable speed primary

When you get into the jungle of coding, I recal seeing parameters for variable speed primary pump regulation, when will they let us north american cave men harness the full power of this machine?

Paul Pollets

I agree...

It is highly unlikely you need 35gpm flow rate to the LLH. If your system load is indeed 35gpm, (not including the DHWT load) than you need the corresponding flow into the LLH.

For example, If your system is using 15gpm at design, than you'll need the same 15gpm flowrate in the boiler pump. A good software program will tell you the correct flow requirements for the system. That makes it easy to select the proper pumps.

CMadatMe

Solved

Thank you Moe for the lesson. Feel stupid....NEver even thought to make a graph and find where the head of the boiler and the curve of the 0011 intercept.



22gpm @ 12' head...



260,000 divided by (22x500) = 23.6 degree delta



Will never and would never use the 0011 pump but now to graph the 00R which I think is the right Taco pump that will work.

bob_46

Delta P

You need to draw a system curve. Viessmann gives you a complete curve which is nice.

For any known pressure drop it's cake to figure what the pressure drop will be at other flow rates or vise versa. Use scale 5 on your system Syzer. Set known Ft. head opposite known GPM and read off any other head VS. GPM. Not just for heat exchangers but whole systems. Plot this on the pump curve and that is where it will operate.

NYplumber

Plotting

On what software are you plotting the points?



The graph I supplied Chris was hand written.

bob_46

Graph

I'm too old for software,I have to use a magnifying glass to read my Syzer.Let's see it says Bornquist $2.00. I have the Mfg. curves in large loose leaf books. I just plot the system curve right on the actual pump curve from the Mfg. cut sheet for that pump. By hand using

the info from the syzer.