Head Loss & Circulator Selection

Brent H.

I'm hoping you folks can help me with determining if I'm doing my head loss calculations correctly and also how to pick the correct circulator.

I have 3/4" Fostapex running to and from an addition which has 3 zone valves located in it. The total heat load in the addition is 25K BTU. For head loss calculations, I used the following information(the worst case zone):

- 25000 BTU(Total for all zones)

- 20 Degree Delta T

- 266 Feet of PEX (Including Coupling Equivalents)

- 21 Feet Copper (Slantfin Baseboard)

- 20 Feet of Copper for Zone Valve Equivalent Head Loss

Using information I found at the slantfin website, I determined that the Copper Head Loss = .56, PEX Head Loss = 4.2, for a total of 4.76 feet of head loss at 2.5 GPM of flow.

A few questions:

1. Does this seem about right?
2. Any suggestions on which circulator to use? This is less than most pumps are designed for.
3. My current system has the circulators on the return side. Eventually I want to convert to pump away but for now might leave as is. Does it matter for pump selection if I'm pumping away or not?

Thanks in advance.

Cam_2

Download WILO Select

http://www.wilo-usa.com/cps/rde/xchg/us-en/layout.xsl/2207.htm

And you can let WILO do the engineering for you. Let the manufacturer work for you!

Rick