I have been interested in building a new plumbing system with hot water
recirculation. I just found this install guide from Grundfos that has some
good information (PDF file)

http://www.us.grundfos.com/web/Download.nsf/Pages/D6774D5BEBD2117B8825652200650E2C/$File/Uprec-gd.pdf

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Jedd Haas - Artist
http://www.gallerytungsten.com
http://www.epsno.com