Boiler Feed Pump Calculator
Size a boiler feed pump from steam rate or feedwater flow. Calculate blowdown allowance, TDH, shaft power, motor kW, suction velocity, NPSHa and annual energy cost.
Project inputs
Change any value to update the result. Units, boundaries and conditional fields are validated by this calculator’s own engine.
Boiler Feed Pump Calculator results
How to use the boiler feed pump calculator
This boiler feed pump calculator uses a dedicated engine, live visual and explanations specific to this problem. Review the assumptions before using the output for purchasing, design, grading, pricing or operational decisions.
What this boiler feed pump calculator solves
A boiler feed pump must deliver enough mass flow to replace steam generation and blowdown while overcoming boiler pressure, elevation, piping loss and control-valve allowance. This calculator combines those requirements in one transparent duty-point estimate instead of treating flow, head and cavitation as unrelated checks.
Flow and total dynamic head
Steam-rate mode converts the selected production unit to mass flow, divides by one minus the blowdown fraction, and applies the design margin. Direct-flow mode is available for measured or specified feedwater demand. Total dynamic head includes pressure head between suction and boiler, static lift, straight-pipe and fitting allowance, and valve head.
Power, NPSH and suction velocity
Hydraulic power is based on density, gravity, flow and TDH. Pump and motor efficiencies convert hydraulic demand to shaft and electrical input. NPSHa uses atmospheric and tank pressure, water vapor pressure, static suction head and suction losses. Always compare the result with the manufacturer’s curve at the actual flow.
Engineering limits
This is a preliminary sizing and energy tool, not a substitute for a licensed engineer, ASME design review, pump curve selection, transient analysis or boiler manufacturer requirements. Hot condensate, deaerator elevation, flashing, minimum-flow recirculation and standby redundancy can materially change the final selection.
Boiler Feed Pump Calculator questions
How much boiler feedwater flow should I allow?
Start with steam production, account for continuous blowdown and then add a defensible operating margin. The final design must also cover startup, control range and minimum-flow requirements.
Why can NPSHa be low with hot feedwater?
Water vapor pressure rises sharply with temperature, reducing the pressure margin available before cavitation. Elevating the deaerator or reducing suction losses can improve NPSHa.
Does the calculator select a pump model?
No. It produces a duty estimate. Select a pump whose certified curve covers the flow and head while meeting efficiency, NPSHr, materials, temperature and reliability requirements.