missing piece of the puzzle, I mean equation

Alan(CaliforniaRadiant)Forbes

Pressure drop - Longest run in feet. Add 50%. Times .04 . This is your head in feet.

10 ft. x 1.5 x .04 = .60 ft. of head; add the elbows in and you probably have 1' of head

B & G IAS = ? (call the manufacturer); I would guess no more than 1 ft. of head

ESBE TV = ? (call mfg.); maybe another 1' of head

So, 3' of head, 12 gpm; take your choice:

Taco 007
Grundfos 15-52F

Oops; I forgot the boiler. Add in the boiler pressure drop and you're probably still OK.

I don't even think about which pump to use for the primary piping unless I put something weird in.

Best wishes,

Alan






<A HREF="http://www.heatinghelp.com/getListed.cfm?id=53&Step=30">To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"</A>

Mark J Strawcutter

gpm+head=pump

If I understand correctly, pump sizing involves finding one where the performance curve provides the desired GPM flow at the head created by the piping involved.

I'm OK with the GPM part, but am having trouble determining the head.

In particular, primary loop for a 120Kbtu output boiler.
About 10ft of 1-1/4 pipe, B&G IAS, ESBE TV and a half-dozen elbows. Oh, and the boiler itself :-)

Everything I've been able to find talks about "length of longest loop" which is OK for secondary circulators. How do you guys go about sizing circs for boiler loops?

Thanks

Mark

hr

If this link works

It will answer all your questions. If not go to www.pmmag.com click on columns and find Sept. 2000 Siegenthaler column. You will find all the answers there. Bookmark this excellent article.

hot rod

http://www.pmmag.com/CDA/ArticleInformation/features/BNP__Features__Item/0,2379,11743,00.html

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

Mark J Strawcutter

step 6

in that article is what I need help with.

Mark J Strawcutter

Thanks Alan

> B & G IAS = ?

> (call the manufacturer); I would guess no more

> than 1 ft. of head


spec sheet only lists "max flow" of 25gpm

> ESBE TV = ? (call mfg.);

> maybe another 1' of head


Cv is 16.4 which says at 16.4gpm it has 2.31 ft of head
(correct?). Does that mean (12/16.4)*2.31=1.7 in this
case?

> So, 3' of head, 12

> gpm; take your choice:

>

> Taco 007 Grundfos

> 15-52F

>

> Oops; I forgot the boiler. Add in the

> boiler pressure drop and you're probably still

> OK.

>

> I don't even think about which pump to

> use for the primary piping unless I put something

> weird in.


I was originally thinking about a Taco 005 which will do 12gpm at 6ft of head.

The tech topic by Steamhead about oversized circs moving the water so fast thru the boiler that it can't pick up any heat has me paranoid :-) but I guess the couple of GPM more
that a Taco 007 does at that same head probably wouldn't hurt too much.

Mark

hr

Are you looking for

an exact number on the piping? B&G System Syzer or Siggy's Hydronic Tool Box software will allow you to enter pipe size and lengths. Also a table of various fittings and valves and related pressure drop. I think you can download the System Sizer at B&G site.

What type of boiler are you using? Is it in the primary loop. If for instance you are using a copper tube, or small condensor boiler IN the loop, the manufactures lit. will show the pressure drop thru the boiler at different flow rates. This combined with the pressure drop thru the pipe, valves, and fittings will give you the number.

hot rod

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

Bill Clinton

dont sweat too much flow

While moving the water through the boiler faster does in fact result in a smaller temperature increase, that same water goes through that boiler more times in an hour, so it has more chances to pick up heat. Ergo: it all comes down to the same thing: Increased flow will not reduce heat transfer. Usually, increased flow will increase turbulence which will give you slightly better heat transmission, so within sensible limits, high flow rates through the boiler are good.

Bill

Mark J Strawcutter

Yes, boiler is in primary loop

It's an older Burnham cast-iron gas-fired boiler. Burnham makes no recommendation as to min/max flow rates, and says that pressure drop thru it is negledgable.

I'm looking for a fairly accurate number on the piping etc so I can properly size the pump. I'll check out B&G's system syzer - thanks.

Mark