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[idahohay]

One of the on line pex suppliers has a chart to be used in calculating pressure drop in pex and some conversion formulas.

Am I not seeing something right? To get ft of head for sizing a circulator  multiply psi x 2.31. Their chart says:

1psi= .434 ft. head. 

If you divide psi by .434 you get feet of head but to an amateur, that sure was misleading.

I wonder how many used their formula and ordered pumps with the wrong curve?

[Sprinter]

You are correct, it is wrong as many online OWB sales sites are as well. There are some doooseys out there. Some size circulators by the size of the house with no regard to anything else. There was one with whole articles about how there products were to be sized, without any formula or chart in the process.

[Sprinter]

Thanks yotehunter, I think what confuses people is not knowing the difference between static pressure, friction head and dynamic head along with their respective applications.
Even logstors charts show static pressure loss which has zero to do with the friction head we are looking for. Or where they call static or psi ,,,, head loss and it gets confusing with mislabeling.
Static , dynamic or psi are not usable in our friction head loss calculations. As long as their is a loop , supply and return the open or closed system factor doesn't matter.  As our pumps don't pump but they circulate