A typical jet pump is a non-submersible type pump with cast iron housing and either 1/2, 3/4 or 1HP (HorsePower) motor rating. All jet pumps are equipped with a pressure switch which activates/deactivates the pump when system pressure reaches threshold levels. Most jet well pumps are dual voltage (115/230V) meaning that they are capable of operating at either voltage. Majority of these pumps have legs or bottom mounting plate which allows to position the pump on top of a well tank with pump stand (such as select Amtrol Well-X-Trol models). A typical location for a jet well pump is indoors, such as inside the house, garage, barn or a designated booth.
Shallow Well Jet Pumps
Shallow well jet pumps are the basic type of jet pumps, designated for supplying fresh water in applications with vertical water lift at 25ft or less. These pumps are most common and best used in areas with high water table (groundwater level) and high water abundance.
Convertible Jet Pumps
Convertible jet pump is a modified version of a shallow well jet pump with jet ejector assembly located outside the pump, rather than inside. When mounted directly to the jet pump, the assembly will operate as a standard shallow well type jet pump and will work where vertical water lift does not exceed 25ft. However, by removing the jet ejector assembly and positioning it directly in the well, submerged in water, the operating depth of the pump (vertical lift) is increased to 82ft. This construction is very useful for areas with variable water table (groundwater level).
Selecting and sizing a jet pump involves many factors and steps and although it is possible to size the pump with all necessary information at hand, consulting a professional is highly recommended.
Selecting the right size and type of jet pump is important because it directly affects the lifespan, effectiveness and operating costs of the system. An undersized model will deliver less water then needed, while oversize model will consume more electricity. Either case will cause the system to cycle more often, causing excess wear.
One of the main factors in choosing between a shallow well and convertible type jet pump is the vertical water lift, which is the distance between ground surface and the end of the suction pipe (usually, a foot valve) submerged in the well. Where the lift is 25ft or less, a shallow well pump is generally used. For lifts over 25ft but less than 82ft, a convertible jet pump is used in a "deep well" assembly.
Water table is another primary factor and will indicate the distance between the ground level and the surface of the water in the well (no to be confused with vertical water lift).
Well replenishment rate & well capacity are indicators of how fast the well can be replenished, at what rate, and how much water will be available for use. These factors are especially important for drilled and dug wells (which have a limited capacity) and have to be carefully considered. When pumping from a lake or a pond these factors are less important unless the water source has a limited capacity.
Peak demand is an indicator of how much water the pump has to deliver during peak hours. The number is typically expressed in GPM and has to be at or below the maximum GPM output of the pump at given conditions.
All well pumps, including jet pumps offer many advantages over municipal water supply, such as lower utility costs, independent water supply and protection from accidental contamination caused by breakage or backflow in municipal water lines.
The most common use for water well jet pumps is for supplying fresh domestic water to a residential home. Systems with small demand can perform well with a 1/2HP pump, medium – with 3/4 and larger – with 1HP jet pump.
Businesses which occasionally use water in a matter similar to residential use can also take advantage of using jet pumps to supply fresh water.
Jet pumps are very widespread in agricultural industry and often supply drinking water to livestock.
Although pumps used for irrigation are typically within 1-2HP range rather than ?-1HP, depending on the size of the irrigated area they may just as well be used or coupled together to meet demanded output.