When is a flow sleeve required?

Submersible well pump motors are designed to operate with a cooling flow of water over and around the full length of the motor. In water up to 86 degrees Fahrenheit, a flow of 0.25 feet/second for 4” motors rated 3 horsepower and higher, and 0.5 feet/second for 6” and 8” motors is required for proper cooling. If the minimum flow is not maintained, the motor can overheat. In these cases, flow sleeves, also known as flow inducer sleeves, must be used to provide sufficient cooling.

The following conditions require a flow sleeve as the minimum flow rate will not be maintained:

Pump is in an open body of water (for example, here in northern Idaho we have a lot of clients that have submersible well pumps in a lake)

• Large diameter wells (use Franklin Electric AIM Manual Table 6 to determine requirements, shown below) Click here to go to AIM Manual
• Pump is in a rock well or below the well casing
• The well is “top feeding”
• Pump is set in or below screens or perforations
  Table 6 from Franklin Electric AIM Manual below shows the minimum GPM required for proper cooling.