A water pump moves water or fluids from one place to another. The type of pump that best suits your needs depends upon the type of liquid you want to pump, the volume of liquid you require, and the distance you want the liquid to move. However, your most basic concern should be to find out exactly what type of pump it is that you actually need for your application. After identifying your exact application, this guide will help determine what type of water pump you’ll need, so that you do not make a wrong decision or costly mistake.
Most common water pump motors employ a centrifugal force, using rotation or fast-spinning, inverted blades called impellers to transmit velocity to liquids, thereby changing that velocity into flow. Centrifugal-style pumps can operate on a long-term continuous cycle and feature a long lifespan. They are by far the most widely used type of water pumps on the market. Here are some brief descriptions of the most common water pump motors and what they are designed for.
Jet pumps are mainly used to draw water from domestic wells into buildings and function by compressing, driving, raising or reducing pressure fluid, especially by means of a piston or set of rotating impellers. They come in two options, shallow- or deep-well designs, with both sitting above ground. Shallow well jet pumps draw water from one line fixed in wells no deeper than 25 feet. Deep well jet pumps use two lines, one for pulling water, and one for pushing water into a distribution system. Jet pumps for deep wells can pump water that ranges from 25-110 feet deep.
Key features: Horizontal end suction pump with ejector either mounted on the pump (for shallow well services) or located down in the well.
Submersible pumps are ideal for draining or keeping out water from basements and lower level areas, and are also used for draining window wells, pumping dirty water, and more. They feature a sealed motor and push fluid to surfaces as opposed to jet pumps, which create vacuums relying on atmospheric pressure. These can be a more effective solution for pushing greater volumes of pressurized water up from within a deep well, outperforming above ground deep-well pumps with the same size motor. They also come in two designs, utility and trash pumps. When moving just water, use utility pumps. However, if the water contains grit, sand, debris or solids, then a trash (or effluent) pump should be employed.
Key features: Submerged air- or oil-filled motor, plus impellers designed to accommodate fluids of various types. (Oil filled motors help to dissipate heat off motors faster than air filled designs.)
Well pumps (shallow, convertible and deep) extract water from underground sources for Irrigation, potable water supplying and distribution, cooling water, fire pumps, and more. They can include submersible pumps, but also hand operated pumps, injector, jet driven and mechanical or rotary lobe pumps, requiring mechanical components to pump water. Well depth will decide which type of pump is needed. Shallow well pumps work from 0-25 feet deep, convertible pumps work for depth as much as 90 feet, and deep well pumps are capable to as much as 300 feet below ground.
Key features: Available in vertical high motor mount and submersible motor mount designs, with open and enclosed impeller systems.
Pool pumps are located on the dry end of a filtering unit and convert electrical energy into mechanical energy. Its main purpose is to power the pump’s impeller, which moves water into and through pumps efficiently for proper filtration in swimming pools and sauna spas. Although the most popular pump based on simple design, single speed pumps tend to use more power when they run for long periods of time, and therefore may not be the most optimal choice when looking for energy efficiency. Dual-speed pumps are somewhat more energy efficient than a single speed pump because they can be set to run on low during peak hours of use and when the pool is not in use. Higher priced, energy efficient variable speed pumps come equipped with a permanent magnetic motor and can be digitally regulated to any speed, thereby producing less friction and less noise, while maintaining a longer operational life.
Key features: Differing motor speeds, energy efficiency and overall costs depending on your pool or spa size.
Now that we’ve learned about the basic types of water pump motors, how do you know what size pump you need? There are some elementary questions you can answer to help you choose. How much liquid needs to be pumped, for example, and how promptly does it need to be extracted? What is the entire distance from start to end that the discharged fluid will travel from the pump? What is the overall vertical rise from pump to the point highest of the discharge hose or piping? Below are some explanations to help you better understand these important questions.
GPM Discharge Capacity is the rate of speed that water flows from the source to the discharge point, measured in Gallons Per Minute.
Shut-off (Vertical Suction Lift and Maximum Head Lift): Shut-off height is defined as the maximum point vertically that a pump can lift liquid. At maximum shut-off height a pump can be turned on and pumping, but liquid will not move past that point in the pipe. A pump’s individual curve chart, provided by the manufacturer, will list maximum shut-off distance, and show total dynamic head. (TDH is determined by two factors, both static head, and friction loss.) Static head is estimated by measuring from the minimum water entry level the pump can operate to the highest point of piping discharge. Friction loss is the impediment to the flow of water caused by the material of the discharge piping, valve types and number of directional pipe connections employed. Static head and friction loss are then added together to equal the total dynamic head.
Performance curve charts are provided for every individual pump to show their working range, and are very useful to help determine the size of pump you may need. These invaluable charts display a graph of how many gallons per minute (GPM) liquid will flow at a given piping height discharge rate. You normally want the liquid to flow at the fastest rate possible at the required discharge height for your installation. This is why it’s essential to know the distance of the total vertical rise from a pump to the highest point of the discharge pipe. The higher your vertical rise, the slower your gallon per minute flow rate will be. On the other hand, the lower a vertical rise is, then the higher the gallon per minute flow rate will be. When you are looking for pumps, be sure you are scrutinizing the GPM flow rates of the pumps at the same height level.
Horsepower (hp) is a unit of measurement of power, or the rate at which work is completed. Electric motor horsepower ratings are ordinarily calculated using torque and speed. For pumps units, this rating should also include the size of the impeller that pushes the liquid. In other words you should always compare the clear liquid or solids capacity, performance curve charts and electrical amperage when purchasing sump pumps, effluent pumps and sewage ejector pumps. And, bigger is not always better, which is sometimes the case when choosing your pump. The higher the horsepower rating for a pump, the stronger its pumping capabilities will be. Nonetheless, using a pump with larger horsepower than you really require can lead to premature pump breakdown. (Most wear and tear on any pump begins at start up and the heat generated later by the motor windings.) So, the longer a unit is allowed to consistently run, the more its windings will cool down. Therefore, you may end up replacing your pump sooner than needed because it’s more than you require for your application.
Amps and Volts: When choosing pumps always compare the amperage; the lower the amp rating the better. Pumps that feature lower amp usage are more economical because they consume less energy. Most pump units are available in 115 or 120 volts, and will easily plug into standard electrical outlets. Pumps that require 230 volts, or 208-240 volts most often use fewer amps to run, and may not be compatible with your building’s electrical wiring. Always make sure that your circuit breaker panel is big enough amperage-wise to handle the electrical draw of the pump you are intending to use.
With a variety of water pumps available on the market, it can often be difficult to assess if you are purchasing the correct one. Knowing pump types and remembering to take note of your performance and height needs before starting your search will ensure the best selection is made for your application.
Product Compliance and Suitability
The product statements contained in this guide are intended for general informational purposes only. Such product statements do not constitute a product recommendation or representation as to the appropriateness, accuracy, completeness, correctness or currentness of the information provided. Information provided in this guide does not replace the use by you of any manufacturer instructions, technical product manual, or other professional resource or adviser available to you. Always read, understand and follow all manufacturer instructions.