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Head calculation for proper pump size: Stumped
I'm going crazy trying to figure this out ... Hot Rod was nice enough to figure out the head and flow for my 11 loops of 3/8 Pex feeding the radiant panels on what I call Manifold #4. Can't find such a cool calculator. Can anybody direct me to one .. or an online table?
I'm trying to understand how to do the calculations for the 3 other manifolds and how they all interact with a single pump. #1 is 7 loops of 200' in 1/2 PexAL #2 is 5 loops of 200' PexAL and #3 is 8 loops of 225' Pex. Just for information #1 and #2 are in my Warmboard and #3 is a slab.
The Viessmann boiler is piped w/ LLH and the 1 1/4 copper line off the LLH has the branches off to the manifolds -- My goal is one pump. The only thing I can find when I punch in the numbers keeps coming up with about 4ft of head for each loop -- but I don't think I am doing it correctly. The Alpha 2 is 19ft head .. that's tight if I am correct with the 4ft each. Do you just add them up 4+4+4+6 = 18. The 11 loops of 3/8 has a zone valve for the whole manifold ... but I really think it's going to end up being "on" most of the time. I went with Cross manifolds for the other 3 as some of the loops many need some high limit control and the Cross make connections to Tstats easy.
The guys doing this would normally used 4 more pumps -- one for each manifold ... that seems crazy. I already have the 3 speed for the indirect and an Alpha for the boiler loop -- and one for the hot recirculation. It seems with modern pumps one should work.