Free boiler feed pump calculator: WHP and BHP from GPM, TDH, SG, efficiency; BHP sensitivity bar chart, hydraulic vs shaft overhead stacked bar, scenario table; guide covers BFP sizing, deaerator context, NPSH, VFD feed pumps—not a stamped design.
Summary: Estimate water horsepower (WHP) and brake horsepower (BHP) for a boiler feed pump (BFP) from GPM, total dynamic head (TDH) in feet, specific gravity (SG), and pump hydraulic efficiency. Uses the common U.S. shortcut WHP = (GPM × TDH × SG) ÷ 3960, then BHP = WHP ÷ η. Charts show BHP sensitivity to flow/head nudges and a hydraulic vs coupling power split bar for your base case.
Engineering reality check (tap to expand)
Not modeled:NPSHa vs NPSHr, minimum flow / recirc, viscosity, deaerator transient, multi-pump runout, VFD curve shape, or vendor test block tolerances.
Does: quick hydraulic kW-ish feel for meetings and training—then you pull the approved water balance, control valve authority, and pump curve from the OEM.
Educational estimator only—not a stamped design basis.
Whether you are sanity-checking a heat balance line item, comparing a constant-speed BFP story to a VFD retrofit narrative, or translating a consultant’s “we need about X hydraulic kW” into horsepower at the coupling, the denominator is honest physics and the numerator is whatever TDH you believe today.