mcgill

mcgill

I'm trying to select a pump for a high efficiency boiler and i have determined the equivalent linear foot of pipe for the primary loop. The manufacturer of the boiler provides the foot of head loss for the boiler. Now i want to add the two together but i do not know how do i convert the equivalent linear foot to feet of head? HELP!!

Ironman

This is Becoming a Popular Question of Late

Check out the attached thread:



http://www.heatinghelp.com/forum-thread/135487/tradeservices-tech

mcgill

Simple Hydronics

Ironman

thanks for the reply. Perhaps i worded the question incorrectly or i am missing something that you've written. Here goes - I understand all that you conveyed and i am able to do that exercise. What i'm missing is where do i find the formula or is there a chart, table, or curve that will show me how to convert 19 linear feet of  1-1/4" copper pipe to foot of head.

The 19 linear feet of pipe consists of - pipe, elbows, valves, flanges, etc.

CMadatMe

Rule of Thumb

I'm confused. Are you talking about pri/sec piping and your looking to size the system side pump and zoning with zone valves? If that is the case you are measuring wrong.

You would first have to calculate the longest run from the outlet of the circ through the longest zone and then back to the inlet of the circ.

19 feet of pipe is nothing in head.

19 x 1.5 x .04 = 1.14ft head

Rule of thumb formula

Longest Run x 1.5 (fudge for fittings, vlvs, etc) x water moving at 4ft per sec. I think if would be easier for us to help you out if you provided a piping diagram and posted it so we can see what you are attempting to do.



If your trying to see the head of one pump then you need to measure the length of run from the outlet side of the pump through the longest zone then through the boiler and back to the inlet side of the pump. You then add the head in the boiler.



Also a varible speed pump such as an Alpha should only be used in the setpoint mode not auto adapt if your using this as a boiler/system pump.

mcgill

Simple Hydronics

Chris,

Again thanks and I'd be glad to post a sketch which I'll do when i get to the office. But here is some additional information.

I am trying to select the primary loop pump for a munchkin contender. The primary loop consists of 12' of 1-1/4" piping, two elbows, two ball valves and a taco hydro separator. How do i convert the equivalent linear foot of pipe to foot of head so i can go to the cure and select a pump. Sorry if i'm not able to convey this more intelligently i can only work from where i am



Jim

CMadatMe

Over Thinking

Your over thinking this. The chart in the install manual gives you the pri pump to use. The head loss in what you are giving is minimal maybe a ft if your lucky. What delta-t are you going to run through the boiler? 

mcgill

Simple Hydronics

Yes i do over think things. But i recently had trouble with an install and came to find out that the primary pump that is recommended over pumped and created a problem. Having not encountered this in the past 50 primary secondary installation that i've done i want to be sure i learn what i need to avoid this or other flow problems in the future. The easy solution to the problem was to build head with the use of a ball valve. But i want to more closely analyze the pump selection. As you can tell i am lacking some technical knowledge. Again How does one convert 50 feet of "equivalent" pipe into foot of head??

CMadatMe

I gave you

Rule of thumb forumal for head in the post above. You should do to the Store here and purchase Modern Hydronic Heating 3rd Edition. Great reference tool to keep on the shelf.



Here's an article for you to read.



http://www.pmmag.com/Articles/Column/48e523c5200d7010VgnVCM100000f932a8c0____