Hot Water Recirc Pump Head

Pump head from pipe length, fittings, target flow.

Run the calculator

Example

You enter

Pipe length one-way (ft) 100
Fittings count 8
Target flow (gpm) 4
Internal diameter (in) 0.75
Material copper

You get

Pump head 6.79 ft
Pressure 2.94 psi
Equivalent length 16 ft

Details, formula, and sources

Recirc head = friction loss along the recirc loop at design flow + minor-loss allowance for fittings. Sized for the longest closed-loop circuit per ASHRAE Handbook hot-water recirculation guidance.

ASHRAE Handbook (HVAC Applications) by name; Hazen-Williams (AWWA M11 5th ed.) for friction.

ASHRAE Handbook licensed; ASHRAE 90.1 read-only at ashrae.org.

Estimate. AHJ and licensed plumber / gas fitter govern. Verify against the IPC / IFGC edition adopted in your jurisdiction.

Field names used by the API: pipe_length_ft, fittings_count, target_flow_gpm, internal_diameter_in, material, head_ft, pressure_psi, equivalent_length_ft

Design recirc flow 0.5 gpm per branch unless user suppliesASHRAE Handbook typical
Minor-loss factor 20% of straight-pipe frictionengineering practice