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Constant pressure circ selection
I have a system where they have lost numerous heating pumps over the last 12 years, 4 pumps, I believe. Single heating loop pump. I'm looking at putting a constant pressure pump in. There's two zones, one in the basement by the boiler the other zone is up in the third floor attic. I measured the equivalent length for the upstairs as nearly as I could and I come up with approximately 14 to 15 feet of head resistance. The downstairs Loop is about 8 feet of head resistance.
(Both loops go to AHU coils that get approx 5 gpm.)
Taco VRs seems to fall on the high side. Grundfos Alpha 15 too small and 26 too big. (I think)
System recieved a new boiler and PS piping.
Currently has Armstrong S35 bolted to 1¼" flanges!