Pump head

Nick_16

I read the article on this web site about sizing pumps and it made things a lot clearer to me. However, when calculating pump head, how do you account for zones? For example: I am setting up an 8 zone system in my own home with a 20KW electric boiler. 4 standard baseboard zones and 4 radiant in-floor zones. None of the baseboard zones are over 100 feet from supply at the pump to return at the pump. Of the 4 radiant zones, the longest is a 4 loop zone of 255 ft. each loop. Which tell me around 6 ft. head. But, isn't that only for one zone being on at a time? What if 3 zone are running at the same time and each was 100 feet in length? Wouldn't your head then be 18 ft.? The Pex is 1/2" and the baseboard is 3/4". Any help would be greatly welcomed. Thanks!

DanHolohan

Figure the pump head

on the one zone with the highest pressure drop. The rest will take care of themselves. Figure the flow rate on the needs of all the zones.