Well Pump Installer key terms

A pump and motor assembly sealed in a watertight housing and installed below the water level inside a well. It pushes water up through a drop pipe to the surface.

A surface-mounted pump that moves water by forcing part of the flow through a narrow nozzle, creating a vacuum that draws more water from the well. Shallow and deep well versions exist.

A sealed tank with a precharged air chamber that stores pressurized water. It limits pump starts and keeps water pressure steady between pump cycles.

A fitting attached to the well casing below the frost line that connects the drop pipe to the horizontal service line. It lets the pump be removed without digging up the line.

A one-way valve that lets water flow in only one direction. In a well system it stops water from draining back down and prevents the pump from spinning backward.

A check valve installed at the bottom of a suction pipe on a jet pump system. It holds water in the pipe so the pump does not lose its prime.

A rubber or plastic device clamped around the drop pipe near the pump. It cushions motor starting torque and helps keep the pump centered inside the casing.

The vertical pipe that carries water from the pump up to the wellhead. It also supports the weight of the pump and is made of steel, PVC, or polyethylene.

The pipe lining the borehole that keeps the well open and blocks soil and surface water from entering. It is usually steel or PVC and must meet local construction rules.

A cover and gasket assembly that closes the top of the well casing around the pipes and wires. It keeps contamination out and supports the drop pipe.

The total pressure energy a pump must supply, expressed in feet of water. It includes lift, system pressure, friction losses, and elevation differences in the discharge piping.

The level of water in a well after the pump has been off long enough for the water to stabilize. It is measured from a fixed point at the wellhead.

The water level in a well while the pump is running at a steady rate. It is lower than the static level because pumping creates drawdown around the well.

The drop in water level in a well caused by pumping. It equals the static water level minus the pumping water level at a given flow rate.

The volume of water delivered per unit of time, usually expressed in gallons per minute. It is matched to the well yield and the building's water demand.

A manufacturer's graph showing how a pump's flow rate changes with total dynamic head, plus efficiency and power input. It is used to select a pump that meets the system demand.

The maximum rate at which a well can supply water sustainably, usually expressed in gallons per minute. It is found by a pump test or from driller records.

The pressure lost as water moves through pipes, fittings, and valves because of resistance. It increases with flow rate and pipe length and must be included in head calculations.

The depth at which the pump intake is placed in a well. It must be below the drawdown water level but high enough above the bottom to avoid sediment.

An electrical control that starts and stops the pump motor as system water pressure changes. Its cut-in and cut-out settings define the operating pressure range.

A submersible motor with starting components built into its housing that needs only two power leads plus a ground. It does not require a separate control box.

A submersible motor with three power leads plus a ground that requires a separate control box containing a starting capacitor and relay. It is common in larger horsepower sizes.

A surface-mounted enclosure that holds starting components such as capacitors and relays for a three-wire submersible motor. Two-wire motors do not use one.

An electrical part that stores and releases energy to help a motor start or run. A failed capacitor can stop the pump from starting or cause the motor to overheat.

A test instrument that applies a high DC voltage to measure insulation resistance of motor windings and cable. Low readings point to moisture or damaged insulation.

A protective device that shuts off power when it senses a small current leaking to ground. It lowers electric shock risk around water and is often required for pump circuits.

An electronic controller that changes the frequency and voltage sent to a motor so pump speed can vary with demand. It can hold constant pressure and reduce cycling.

The current a motor uses while running, measured with a clamp meter. Comparing it with the nameplate rating helps find overload, low voltage, or mechanical problems.

A cement or bentonite mixture placed in the space between the well casing and the borehole wall. It seals the annulus and blocks surface water and shallow groundwater.

Electrical cable made for underwater use that connects the motor to the surface power supply. It must be correctly sized, supported, and spliced to resist moisture.

The process of adding chlorine to a well and water system to disinfect it after installation or repair. The solution is held for a contact time, then flushed out.

The initial commissioning checks after installation, including voltage, motor rotation, amp draw, pressure settings, and flow. Proper startup confirms the system works within its design limits.

The forming and collapse of vapor bubbles in water when pressure drops below its vapor pressure, often at the pump intake. It causes noise, vibration, and impeller damage.

A pressure surge caused by a sudden change in water velocity, such as when a pump stops or a valve closes fast. It can damage pipes and fittings.

Rapid on-and-off operation of the pump, usually caused by a waterlogged pressure tank, wrong pressure switch settings, or a leaking check valve. It shortens motor life.

Operation of a pump with little or no water at the intake, which can overheat the motor and damage seals and impellers. Dry-run protection shuts the pump off first.

A control feature that detects low flow, low pressure, or low current and stops the pump when water is unavailable. It prevents overheating and damage to pump and motor.

A safety procedure that isolates electrical or mechanical energy and attaches a lock and warning tag. It prevents accidental startup while a pump or control is being serviced.

A work area with limited entry or exit that is not meant for continuous occupancy, such as a well pit or vault. Entry requires air testing and a rescue plan.

Devices or practices that keep contaminated water from flowing backward into a well or public supply. An air gap or check valve may be required by plumbing codes.