Re-Calc: cut flow rates by 50% for 1/2" pipe limits

Posted by Eiclher on July 04, 2006 at 11:45:33:

In Reply to: Re: Please Check my calcs posted by HeatPro on July 01, 2006 at 23:39:49:

For the parallel loops I used the equation Parallel_Head = (H1*H2)/*(H1+H2) and increased each parallel connection by 5% for the valves and header pipes. I iterated this calculation over the 10 parallel loops, at a 1.6 gpm max flow rate for a 1/2" pipe .

The total flow rate is the sum of all 10 of the individual loop flow rates. ~13.44 gpm

4 loops of 250' at 1.6 gpm with 12' head each
4 loops of 250' at 1.3 gpm with 10' head each
2 loops of 150' at 1.0 gpm with 8' head each

TOTAL HEAD for 10 loops = 1.3'
TOTAL GPM for all 10 loops = 13.44 gpm

There are valves on each loop, and it is possible to have a higher head pressure with lower gpm flow rates when fewer parallel loops are fully opened.

If I purchase a boiler with a local circulator pump, then the second radiant circulator pump should be capable of ~ 2' head at 14gpm, or 12' head at 2gpm

If I purchase a boiler without a local circulator pump, then the single circulator pump should be capable of boiler' + 2' head at 14 gpm, or boiler' + 12' at 2gpm

My current system has just one large 1/6 HP circulator pump.

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