Pond Pump Glossary

Pump Terms...

• Inlet/Intake - Refers to the opening through which water enters the pump head.
• Outlet/Discharge - The opening through which water exits the pump.
• Flooded Suction/Gravity Fed - Liquid source is higher than the pump, and liquid flows to pump by gravity. Recommended for centrifugal pump installations.
• Shutoff - Point in which pump will not push water passed the listed feet in a vertical column . No flow past the listed vertical feet. This does not effect the horizontal run but if the run is very long say 50 or 100 ft. then friction comes into play.
• Flow - The measure of the liquid volume capacity of a pump. Given in Gallons Per Hour (GPH) or Gallons Per Minute (GPM) , as well as Liters Per Minute (LPM) and Milliliters Per Minute (ML/M).
• Head - Another measure of pressure, expressed in feet. Indicates the height of a column of water being lifted by the pump, neglecting friction losses in piping. If pump is submerged, the head can be measured from the surface of the water. Head ( Ft. of Water) = 2.31 PSI. Example: 10 feet equals 4.32 PSI.
• Seal-less - No seal is used, power is transmitted from the motor to pump impeller by magnetic force. Example is Magnetic Drive Aquarium Pumps and Wet rotor pumps. Example : Little Giant aquarium pumps, PES Wet Rotor Models (most mini pumps) and Cal "P" Models.
• Submersible - A pump which operates only when totally submersed in the fluid which is being pumped, with water-proof electrical connections or cord , using a motor which is cooled by liquid.
• In-Line - A pump which operates in open air , by connecting tubing to the inlet and discharge outlet.
• Dual Purpose - This versatile pump category is designed to operate submersed or in-line.
• NPT - Refers to the National Pipe Thread standard measurement.
• MNPT - This refers to female pipe thread, in which the threads are on the inner side of the connection fitting.
• Thermally Protected - Mechanically safety device in the motor to prevent overheating.
• Impedance Protected - A non-mechanical method of preventing motor overheating. The motor coil is designed to "impede" excess current, resulting in a stabilized motor temperature.
• Barbed Fitting - As apposed to a threaded fitting , rings projecting outward around fitting designed to grip hose. Usually measured in O.D. (outside diameter) , as apposed to hose measured in I.D. (inside diameter).
• Quick Disconnect - Fittings that are locked on the the pump ports with a latch or locking device to convert pump ports to threaded or barbed connections , usually used on high pressure pumps.
• Relay - Electrical solenoid with heavy contacts designed to absorb high current or high amp draw , usually for motors with 3 HP or larger or used with sprinkler timers to activate a sprinkler pump. Coil voltage of solenoid may vary depending on control device, usually coil voltages come in 24V , 110V or 230V AC , amp and horsepower ratings for contacts are usually listed.
• Kilowatt(1000 watts) Hour - Electrical measurement designed to bill customers based on usage per hour. Watts are listed for every unit , power consumption and cost is dependent on the KILOWATT HOUR charged in your area. If a pump states that it uses 1000 watts and your power company charges you 10 cents a kilowatt hour then it cost's you 10 cents an hour to run that unit and if the pump list's 250 watts then it cost's you 2.5 cents per hour to run that unit.
• Centrifugal pump - moves water by displacing liquid from the center of the impeller as it spins to the outer part of the impeller creating a vacuum in the center by means of centrifugal force. The diameter of the impeller predicts the pressure and the width predicts the water flow. Impellers can spin at 3600 RPM and 1800 RPM and other speeds , all fountain pumps are centrifugal. This type of pump is not self priming except in the case of sprinkler pumps , pumps with leaf baskets and pumps with foot valves installed (jet pumps).
• Positive Displacement pump - remove water from a cavetti or cylinder by directly applying pressure to a diaphragm or piston or a flexible impeller and cam. Check valves are used to preserve the pressure down line except in the case of the flexible impeller and cam. Usually diaphragm or flexible impeller or piston pumps are used for more exact amounts of water and for higher pressures. This makes them ideal for solar applications , RV's, pressure washers, small cabins, R.O., misters or situations where water demand is low but pressure demand is high. A centrifugal pump is limited in the pressure it can produce unless the design of the pump allows for impeller stacks. This type of pump is usually self priming a few feet.

Types of Pond Pumps

• Large Volume Plastic pumps - These pumps utilize a permanent split capacitor (PSC) motor sealed in a Stainless Steel Housing, which in turn, is surrounded by a plastic case. The PCS motor allows these pumps to use less energy than other pumps of similar flow capacity. The motor also produces less heat ; therefore, the pump does not require oil internally. These pumps are ideal for use in waterfall and stream applications, found in water gardens.
• Epoxy Encapsulated (Potted) Pumps - These pumps feature an epoxy-encapsulated motor, plastic housing, and radial lip seal on the motor shaft. They provide enough power to effectively operate a water garden, statuary or tabletop fountain. Algae build-up does not effect these small, powerful workhorses. In fact, they may even be used in some harsh, industrial-type applications. These "potted" pumps are usually more compact in size than an oil-filled pump of equal flow capacity.
• Wet-Rotor (Hysteresis) Pumps - The wet-rotor pumps, often mistaken as magnetic drive pumps, utilize an epoxy-encapsulated motor and plastic housing. A permanent magnet is attached to the impeller. The magnet acts as the rotor would in a conventional motor. The water being pumped surrounds the rotor, thus the term "wet-rotor". They are seal-less and oil-less. These pumps work well in water garden, statuary, and some industrial applications. They are the most compact and energy efficient type of pump manufactured. The other side of this efficiency is very little starting torque. therefore, these pumps do not produce as much pressure and will not pump water as high as as their epoxy-encapsulated counterparts.
• Permanently Lubricated Pumps - Without exception , these pumps offer the ideal combination of assets. The oil-filled motor housing design also features a radial lip seal on the motor shaft. They have an exceptional life expectancy, because the oil serves as a continuous lubricant for all the moving parts and the shaft seal. This non-toxic oil, often paired with an aluminum, cast iron, or plastic housing, also helps dissipate heat build-up found in continuous-running pumps. Therefore, the motor stays cool and extends the life of the pump.