Pump reference
A plain-English glossary for pump rooms, wells, basements, pools, irrigation fields, fire pump rooms, and anyone trying to tell PSI from GPM without summoning the Cavitation Goblin.
How to use this glossary
Pump words are practical. “Pressure,” “flow,” “suction,” “discharge,” “curve,” and “cavitation” are not vocabulary decorations. They point to real operating conditions.
When a pump misbehaves, the right word can keep you from replacing the wrong part.
A machine that adds energy to liquid so it can move through a system.
The power source that turns the pump shaft or drive mechanism.
A rotating part that gives water velocity and energy in many centrifugal pumps.
The pump body that guides liquid from the impeller toward the discharge outlet.
A spiral-shaped casing area that helps convert velocity into useful pressure.
The rotating part that transfers motion from the motor to the pump.
A component that helps keep water from leaking where the shaft passes through the pump.
A support component that helps rotating parts move smoothly.
The inlet side where water enters the pump.
The outlet side where water leaves the pump.
Height-related pressure requirement before friction and other losses are added.
The full head requirement including lift, pressure, friction, fittings, valves, and equipment.
Pressure or head lost as water moves through pipe, fittings, valves, filters, and equipment.
The condition of the pump and suction line being filled properly so pumping can begin.
Net positive suction head; a suction-side concept tied to avoiding vapor bubbles and cavitation.
The target operating condition: the desired flow at the required head or pressure.
Force in the system, often measured in PSI.
The amount of liquid moving over time, often measured in GPM.
Pounds per square inch; a common pressure unit.
Gallons per minute; a common flow unit.
A manufacturer chart showing pump performance at different flow and head conditions.
A representation of the resistance the piping system creates at different flow rates.
Where the pump curve and system curve meet in actual operation.
A condition where a pump runs against a closed or blocked discharge with little or no flow.
A level switch that starts or stops a pump as water rises or falls.
A switch that starts or stops a pump based on system pressure.
A device or panel that manages pump operation and protection.
Variable frequency drive; a controller that can adjust motor speed.
A protection strategy to stop or prevent pump operation without adequate water.
A valve that allows flow one way and helps prevent reverse flow.
A valve used to relieve pressure under certain conditions.
A signal that warns of high water, low pressure, controller fault, or another abnormal condition.
Vapor bubbles form and collapse inside the pump, causing noise, vibration, and damage risk.
Air entering the suction side, reducing performance and confusing diagnosis.
Rapid pump starts and stops, often caused by control, tank, leak, or sizing problems.
A shock or banging event caused by sudden changes in water velocity.
A blocked screen or basket that can starve the pump.
Not enough water moving through the system.
Not enough force available at the point where pressure is needed.
Excess heat caused by poor flow, deadhead conditions, motor problems, or improper operation.
A common pump type that uses a spinning impeller to move water.
A pump designed to operate while submerged in water or liquid.
A pump used to raise usable pressure in a system.
A pump used to move groundwater from a well.
A pump used to remove unwanted water from a basin or low area.
A pump used to circulate pool water through filters and equipment.
A pump used to deliver water to sprinklers, emitters, fields, tanks, or zones.
A code-regulated life-safety pump used to support fire protection systems.