Submersible pump motors require water flow over them to dissipate heat. In open water, such as a lake or cistern or in large diameter wells, heat dissipation becomes a problem since water is likely to flow directly into the intake of the pump, instead of flowing over the motor. In these situations, a pump sleeve or shroud is required. Pump sleeves are also required if the well is top feeding (water flows in from above), or if the pump is placed below screens or perforations, and sand is able to fall into the pump inlet. As a side note: pump sleeves, flow sleeve, flow inducer sleeve, and pump shroud all mean the same thing!
A PumpSleeve / FlowSleeve is simply a PVC pipe that prevents water flow into the pump from the lateral directions, and directs waterflow to enter from the motor's end, allowing for water to pass over the motor first before entering the intake.
PVC pipe with thinner wall ( e.g. Class 125 or SDR 35) usually has larger inside diameter, which is recommended to use for making a pump sleeve.
Below is a chart for minimum flow rate required by the motor per well casing diameters. If your pump operates at a lower flow-rate than stated, you will require a pump sleeve.
Buy a pump sleeve kit at https://www.tuhorse.us/categories/parts-and-accessories/pump-sleeve-kits.html
|4 inch motor||6 inch motor|
|Well casing diameter||Min. GPM||Min. GPM|