How To Replace A Pentair Whisperflo Pump Motor


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The motor on your Pentair Whisperflo pump has stopped working and it's time to install a replacement. This guide/video will walk you step-by-step through the process of how to replace a Pentair Whisperflo pump motor.


Step by Step


Step 1

Turn Power Off - Make sure the power to the pump is turned off at the breaker.

Step 2

Remove Seal Plate Bolts - Using a 9/16" socket wrench, loosen and remove the 6 bolts that secure seal plate to the front Whisperflo pump housing.

Click Here to View Pentair Whisperflo Parts

Step 3

Slide Motor Back - Slide the motor assembly back and away from the pool pump housing.

Step 4

Remove Bonding Wire - Locate the bonding wire and remove it from the bonding lug on the pump motor. The bonding wire will usually be exposed copper or a copper wire within a green sleeve.

Step 5

Remove Back Cover - Remove the cap or plate in order to gain access to the wiring terminal.

Step 6

Disconnect Wires - Disconnect all hot, neutral, and ground wires from the terminal board.

These will be the wires that are coming into the motor from the conduit hole.

Step 7

Pull Wires - Pull the disconnected wires out of the motor through the conduit adapter.

Step 8

Move Motor - The motor is now disconnected from the front housing and electrical wires. It can be moved to a location where it is easier to complete the motor replacement.

Click Here to View Pentair Whisperflo Replacement Motors

Step 9

Remove Conduit Adapter - Remove the conduit adapter from the Whisperflo pump motor.

Step 10

Remove Diffuser Screws - Using an allen wrench, remove the two diffusers screws.

Step 11

Remove Diffuser - Once the two diffuser screws are loose, pull the diffuser away from the motor assembly.

Step 12

Check for Impeller Screw - Look at the center of the impeller and see if there is a screw. If there is proceed to step 13. If there is no impeller screw, proceed to step 15.

Step 13

Stabilize Shaft - In order to remove the impeller lock screw, the shaft at the back of the motor will need to be stabilized. Depending on the style of the motor, you will use a 9/16" wrench or a flathead screwdriver to stabilize the shaft.

Step 14

Loosen Impeller Lock Screw - While stabilizing the shaft of the motor from the back, use a phillips head screwdriver and turn clockwise. 

Note: The impeller lock screw is left-hand threaded (reverse thread). That is why you turn it clockwise to remove it.

Step 15

Remove Impeller - Continue to stabilizer the shaft and spin the impeller off counterclockwise.

Step 16

Remove Seal Plate Bolts - Using a 9/16 wrench, remove the 4 bolts that secure the Whisperflo motor to the seal plate.

Step 17

Remove Seal Plate - Pull the seal plate away from the pool pump motor.

Step 18

Remove Old Seal From Seal Plate - Half of the old shaft seal is in the seal plate. In order to get that out, turn the seal plate over and tap it out using a flathead screwdriver. Be careful not to damage the plastic of the seal plate.

Step 19

Remove Old Seal From Impeller - Using a flathead screwdriver, gently pry the seal out of the impeller.

Step 20

RTV Silicone - Take the spring portion of the new shaft seal and apply a thin layer of RTV silicone around the edge of the metal base.

Click Here to View RTV Silicone

Step 21

Install Spring Seal Into Seal Plate - Press the seal with the RTV silicone into the plate. Place a 1" pvc coupler over the seal and lightly hammer the seal into the plate. Check the front and back of the plate to make sure the seal is flush with the plate.

Step 22

Install Ceramic Seal Into Impeller - With a clean cloth, press the ceramic shaft seal into the impeller with the white ceramic side facing up. 

Note: The clean cloth is recommended so that fingerprints don't get on the ceramic. This could cause the seal to fail.

Step 23

Install Seal Plate - With the new Whisperflo motor in place, slide the seal plate onto the front of the motor.

Step 24

Secure Seal Plate - Take the 4 bolts that were removed in Step 16 and secure the motor to the seal plate using a 9/16" wrench.

Step 25

Remove End Cap - Remove the end cap from the new pump motor.

Step 26

Stabilize Shaft of Motor - Like Step 13, stabilize the shaft of the motor from the back.

Step 27

Install Impeller - While stabilizing the shaft, spin the impeller on clockwise. Turn it until it is firm. The impeller does not need to be over-tightened.

Step 28

Install Impeller Lock Screw - If you removed an impeller screw in Step 14, now is the time to reinstall it. With the shaft stabilized, use a phillips head screwdriver to tighten the screw counterclockwise.

Step 29

Install Diffuser - Place the diffuser onto the front of the seal plate and tighten the two screws with an allen wrench.

Step 30

Install Conduit Adapter - Remove the plug from the conduit hole on the motor and install the conduit adapter.

Step 31

Feed Wires Into Motor - At this point, the new motor can be moved back to the pump housing location. Feed the wires that were removed in Step 7 through the conduit adapter and into the motor.

Step 32

Connect Wires to Terminal Board - Check the wiring diagram on the motor label and reconnect the wires based on the diagram.

In this example, we had a single-speed motor running on 230v. We connected the Black hot line to L1, the Red hot line to L2, and the green ground line to the green screw.

Step 33

Install Motor Cap - Place the end cap on the pump motor and tighten the screw(s).

Step 34

Connect Bonding Wire - Connect the bonding wire that was removed in Step 4 to the bonding lug on the new Whisperflo pump motor.

Step 35

Install Diffuser O-ring - Lubricate the diffuser o-ring with silicone or teflon lubricant and install it on the front of the diffuser.

Step 36

Install Housing Gasket - Lubricate the housing with silicone or teflon lubricant and install it on the seal plate.

Step 37

Slide Motor Into Housing - Slide the pump motor assembly into the front housing.

Step 38

Install Seal Plate Bolts - Secure the motor to the front housing using the 6 bolts that were removed in Step 2.

Step 39

Prime Pump - Remove the pump lid and fill up the trap assembly with water. Reinstall the lid.

Click Here to View Pentair Whisperflo Pump Motors

Step 40

Turn On Pump - Turn the breaker to the on position and run the pump. 

Congratulations!! You've successfully replaced the motor on a Pentair Whisperflo Pump.



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