Pumping Awaaaaaaaaaaaaay

clammy

Alex i hope i am understanding the piping lay out diagram you posted i would believe that by pass circuit setter is set up to by pass so that you will have flow past your 2 closely spaced tees for the 2 radiant loops with out it you would have no flow past those take offs being they are off the primary supply loop and not truely tied into the boilers return piping side ,the rest of the flow would be going through your baseboard risers but i would wonder why there is no circuit setter for those riser nor a bypass but i would think that that main circuit setter on the end of the loop would handle the additianll head when the trv 's are closed but a pdb valve would do it but it probalbly is not neededbecause of the circuit setter eating up unused head .There are some great examples of this in some caleffi handbooks penned by mario doninelli on the subject of there autoflow circuit setter at bit on the engeenering side but a great read in any case ,the design and layout seem to be very european in thought with lower eletrical comsumption in mind ,hope i helped peace and good luck clammy

The Wire Nut

A Question from The Wire Nut (aka Stonehouse)

I'm designing the controls for a hydronic system based on some engineering drawings supplied by my client the prime HVAC contractor.

The system is using a Buderus G334 73. The boiler is drawn with a primary loop in 2" with a "Circuit Setter" at the end set to 3 GPM. The boiler pump specified is a Taco il131 (rated at 25 GPM!) pumping, what for it, pumping IN!

Off the primary loop there 2 sets of risers each plumbed in parallel to the primary loop. None of the risers has a pump(!) and extend from the basement to the roof which is effectively the 6th floor.

The risers are 1 1/2" until the 2nd floor where they seem to be reduced to 1".

These risers feed fin tubes with TRVs in multiple zones on each floor. Remember all without pumps except the boiler pump!

One of the risers has a 1" parallel pull off for the DHW tank and also pumped by a 131.

Also off the primary loop are 2 1" secondary loops, each with a TACO 008, and a 3 way mixer. Each of these secondary loops feeds a radiant floor (zone?) of 10000 BTU. Not sure if each of those radiant zones are actually multiple loops or just large 10000 btu loops.

OK, I'm not a "Heating Guy" per se, nor do I consider myself a designer in any sense, but it just seems to me that this isn't going to fly. 25 gpm pumping on a boiler holding 9.5 gallons? Two 6 floor risers without pumps, on 1" pipe? Pumping in?

Designing the controls "as-drawn" is not difficult, but I want to be prepared for the inevitable finger pointing...

Thanks!

Alex "The Wire Nut" Marx

Steamhead (in transit)

Good eye!

but before we get into this, we would need to know what piping and pumping the boiler needs- they don't tell you much in the online I&O manual. Some boilers, especially some mod-cons, have more internal resistance than others and would therefore need bigger circs. The actual flow rate may be less than 25 GPM if the "head" (back-pressure) is high.

The circuit setter in the primary loop definitely sounds screwy, unless the boiler manufacturer wants it there for some reason. Throttling this down would increase the head and slow the flow rate, but you know that.

Is there any other method proposed to circulate water thru those fin-tube risers- say, with Monoflo tees in the primary loop (which I'm not sure would work anyway)? If not, you'll need to add circs for these loops to your design.

Call me sometime if you want to get into this in more depth. I'm on my regular cell, not the one I was using at Wetstock.

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The Wire Nut

Hey Frank!

Glad to hear from you. I'll definitely give you a shout.

I ran into the same issue with the I&O manual, nothing. Shouldn't have the "I" in the title that's for sure.

I guess the circuit setter is to deal with the Fin Tube and the TRVs with the possibility of the boiler firing but none of the TRVs are open. Considering that those 2 long runs rely on the one big boiler pump I can't imagine much flow beyond the first few floors. I didn't mention that the fin tubes are all in parallel with the risers.

The TACO chart shows a total head of 15' at 25 gpm, which means that 6 stories at 10' a story the head is going to be 4 times that. (They also spec'd the 131 at 208 volts when TACO lists it as a 120 volt pump, there goes the factory smoke).

I've got my tekmar design down for the "as-drawn" but I want to clue the contractor (who is only responsible for the VAC and all the control wiring, there is a plumbing company doing the heating, but not the controls!) that there are some serious issues here and that I'm going to CMA and perhaps he should CHA too!

With any luck, he might be able to get the engineer to read one of Dan's books and at least move that pump to the outlet of the boiler...

AM

Unknown

Static Pressure

"The TACO chart shows a total head of 15' at 25 gpm, which means that 6 stories at 10' a story the head is going to be 4 times that"

Remember that there is a difference between the static pressure head caused by the height of the building and the pump pressure head due to the flow resistance of the piping and boiler.

The pump does not have to pump water up 6 stories, the fill pressure does that. The static fill pressure must be high enough to raise the water to the top of the building. The pump head must be adequate to circulate the required GPM through the boiler and emitters.

From your description it sounds like the risers are piped in parallel with the primary loop with the circuit setter in between the risers. This sort of sounds like the primary loop is actually a bypass, with the setter determining how much flow bypasses the system.

Can you post a drawing of the system?

Steamhead (in transit)

If the circuit setter

is all the way at the end of the primary loop, and all the secondary risers leave the primary and return to it before the circuit setter, than the circuit setter is just getting in the way.

But if the risers leave the primary loop before the circuit setter and return AFTER the circuit setter, that could be used to induce flow in those circuits. That, however, would not be a true primary-secondary setup. And it would not give us any control over the flow in those circuits.

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The Wire Nut

Doh!

Mike, Do I feel dumb and dumber! I knew that, being one of the things I took away from Dan's seminar. Makes perfect sense!

Steamhead: They return after the Circuit Setter, in true "parallel" fashion. I've attached a Jpeg of the drawing for clarity (probably should have done that in the first place!)

AM

[Deleted User]

hey steamy

i'm not very clear on ccs, and i can't give you the details yet, but we just acquired a new acct; 'remodeled' 100yr old, 3flr, 50x100 ft print, 4-6? multi-zone water source heatpumps, and 6 floor/wall mount heatpumps, and unless i wasn't shown an aux pump room, the flow is controlled by ccs, and it's all pumpered by 1, 10hp b&g/don't know the pump#. would the 10hp/'matching' pump account for the lack of other pumps, while using the ccs to control the flow?

Steamhead (in transit)

It very well could

but I'd ask to see the plans, to be sure.

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scrook_3

1 phase or 3?

Looks like Taco offers 131's in both 115/208-230V/60Hz/1phase
and 200V/60Hz/3 phase

Note: motor voltages will generally be nameplate rated at 115, 200, 230, and/or 460 for 120, 208, 240 or 480V service.

[Deleted User]

ask to see the plans?

oh, i'll be spending some more time there soon and i'll see what i can find. it's a new acct, and so far, i've been the one to spend time there, and recently put the chiller back into service after it's spring cleaning

and, i just checked the 'find a pro' link and discovered that we're relatively close. i used to live in silver spring md, and moved to the winchester va area 14 yrs ago. maybe we'll come across one another somewhere along the line. heck, when there's something to learn, i'm willing to travel and work for free. bec i've learned something as i've grown older; the older i get, the less i'll do for money

and thanks for passing along your knowledge

The Wire Nut

The Catalog and submittal sheet have it listed as a 115, while the larger pumps are listed as multi-voltage.

Are the additional voltages for the 131 covered under the "Motors are available with other electrical characteristics — consult your Taco representative" note?

In the pump schedule it's listed as 208/single phase/60 cycles (as if you were still going to find 25 cycle AC in NYC!).

Thanks!

AM

[Deleted User]

many motors are listed in 50hz also,

to make them universal for the global community. kinda like finding instructions in eng, french and spanish. it's also more economical

The Wire Nut

Pretty much everything is listed for 50/60 hertz, though there will be speed and heating penalties at 50 hertz. Don't know where you find 50 hz much in the states anymore. Europe, of course, would have a hard time finding 60 hertz!

Thanks again!

AM

The Wire Nut

Thanks!

Given the circuit setter provides enough pressure drop to allow those mains to function, should the pump be moved from the input to the output side of the boiler?

AM

clammy

boiler type

I would depend upon the pressure drop across the boiler if it a cast iron boiler i would move it to the supply and i believe i would move the indirects supply and return off the secondary supply and pipe them directly off the primary as the secondary circuits are pipe difference being the indirect piping would have its own pump and would be able to operate while your main pump is running unless you wanted it set up as propirity .hope i helped peace and good luck clammy