This calculator determines the flow and pressure relationship of a piping or plumbing system and an associated pump. It has been designed to mainly support those who are designing hot water heating systems who are trying to determine the right size pipe or tube and the right circulator pump.
The system flow rate can be entered directly (GPM) or the user can specify an intended heat transfer rate (BTU/hr) and supply temperature (F) and assumed temperature loss to have the tool determine the flow rate (GPM).
Drop down menus allow the selection of pipe size and circulation pump. Other system details are entered into cells as needed including, pipe length, number of elbows, net elevation change (if an open system) and “other” pressure drop such as a heat exchanger.
The tool determines the pressure drop (ft) of the piping system at several flow rates (GPM), plots this information with pump head (or pressure rise in ft) and flow (GPM), and determines the likely system operating point (GPM, ft) given the combined system. Different pumps can be selected to determine the pump best sized for the system.
An overview of pump and pipe sizing and interactions can be found in the article, Solar Water Pumping Basics on the UVM New Farmer Project Website.
If you have specific pipe types or sizes, additional pumps you’d like to have included or general questions or feedback please let me know.
Currently the calculator includes the following pumps listed in order of half flow capacity. (Half flow capacity noted with the prefix “F” in parenthesis along with half pressure capacity with the prefix “P”).
Bell+Gossett Xylem e3-SC4U (F2,P5)
Laing Ecocirc D5-38/090B (F3,P6)
Bell+Gossett Xylem e3-SC6N (F3.15,P4.5)
Bell+Gossett Xylem e3-SC6S (F3.15,P4.5)
Laing Ecocirc D5 Solar 720B (F3.25,P4.5)
Grundfos 15-10 (F4,P2.75)
Grundfos 15-100 (F4.25,P18)
Laing Ecocirc D5-38/720B (F4.25,P9.5)
Grundfos 15-58 (Lo) (F5,P7)
Taco 009 (F5.25,P17.5)
Bell+Gossett Xylem NRF-9F/LW (F6,P4.5)
Taco 008 (F6.3,P7.25)
Taco 00R (Lo) (F6.75,P7.5)
Taco 00R (Med) (F8,P9.25)
Bell+Gossett Xylem NBF-25 (Lo) (F8.5,P6)
Grundfos 15-42 (F8.5,P7.5)
Grundfos 15-58 (Hi) (F8.5,P9.5)
Taco 00R (Hi) (F9,P10.75)
Grundfos 26-120 (F9.5,P19)
Taco 0010 (Lo) (F10.75,P4.25)
Bell+Gossett Xylem NRF-22 (F11,P7.5)
Taco 007 (F11.625,P4.875)
Bell+Gossett Xylem NBF-25 (Hi) (F12.5,P9)
Bell+Gossett Xylem NBF-36 (Lo) (F13,P12.5)
Taco 0010 (Med) (F13,P4.75)
Grundfos 26-96 (F14,P15)
Taco 0010 (Hi) (F14.75,P5.25)
Taco 0011 (F15,P15.5)
Taco 0014 (F15,P11.5)
Grundfos 43-44 (Lo) (F15.5,P5)
Grundfos 26-64 (F16,P12.25)
Grundfos 26-99 (Hi) (F16,P15)
Grundfos 26-99 (Lo) (F16,P12.25)
Grundfos 26-99 (Med) (F16,P14)
Bell+Gossett Xylem NBF-45 (Lo) (F16.5,P10)
Grundfos 26-99 (F16.75,P16)
Taco 0013 (F17,P16.75)
Bell+Gossett Xylem NBF-36 (Hi) (F18.5,P17)
Bell+Gossett Xylem NRF-33 (F18.5,P6)
Grundfos 26-116 (F19,P18.5)
Grundfos 43-75 (F20.5,P12.5)
Bell+Gossett Xylem NBF-45 (Hi) (F22.5,P13.75)
Taco 0012 (F22.5,P7)
Taco 2400-30 (F28.75,P14.5)
Grundfos 43-44 (Hi) (F31.5,P7)
Currently the calculator includes the following piping options:
Copper 3/8″ – M (light – domestic water)
Copper 1/2″ – M (light – domestic water)
Copper 3/4″ – M (light – domestic water)
Copper 1″ – M (light – domestic water)
Copper 1-1/4″ – M (light – domestic water)
Copper 1-1/2″ – M (light – domestic water)
Copper 1/4″ – L (mid – below ground)
Copper 3/8″ – L (mid – below ground)
Copper 1/2″ – L (mid – below ground)
Copper 3/4″ – L (mid – below ground)
Copper 1″ – L (mid – below ground)
Copper 1-1/4″ – L (mid – below ground)
Copper 1-1/2″ – L (mid – below ground)
PEX 3/8″
PEX 1/2″
PEX 5/8″
PEX 3/4″
PEX 1″
PEX 1-1/4″
PVC 1/2″ 40
PVC 3/4 40
PVC 1″ 40
PVC 1-1/4″ 40
PVC 1-1/2″ 40
PVC 2″ 40
PVC 2-1/2″ 40
PVC 3″ 40
PVC 4″ 40
PVC 5″ 40
PVC 6″ 40
PVC 8″ 40
Black Iron Pipe 1/8” – Sch 40
Black Iron Pipe 1/4” – Sch 40
Black Iron Pipe 3/8” – Sch 40
Black Iron Pipe 1/2” – Sch 40
Black Iron Pipe 3/4” – Sch 40
Black Iron Pipe 1” – Sch 40
Black Iron Pipe 1-1/4” – Sch 40
Black Iron Pipe 1-1/2” – Sch 40
Black Iron Pipe 2” – Sch 40
Black Iron Pipe 2-1/2” – Sch 40
Black Iron Pipe 3” – Sch 40
Black Iron Pipe 3-1/2” – Sch 40
Black Iron Pipe 4” – Sch 40
Black Iron Pipe 5” – Sch 40
Black Iron Pipe 6” – Sch 40
Black Iron Pipe 8” – Sch 40