How to Change a Swimming Pool Water Pump Motor

If You Are Not Good with DIY Electrical Work, Get a Professional

woman adjust swimming pool pump motor
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Unfortunately, there comes a time in your life as a swimming pool owner when you are faced with replacing your swimming pool water pump motor. This may be due to the bearings wearing out so that the motor is making a tremendous racket, or the motor won't run because it is burned out.

Changing the motor is not difficult and can be done by the average swim pool owner provided you are comfortable working with electrical wiring. If not, then get your local pool professional to do this project.

Steps to Change a Pool Water Pump Motor

While every pump on the market may not be exactly like the one described below, they should be similar enough that this will guide you through your motor change.

  1. First, make sure that the power to the pump is turned OFF. This means turning off the breaker at the panel box and not just the switch at the pump.
  2. Most pumps have a motor mounting bracket which is attached to the motor by four bolts (these bolts may not be visible). This piece, in turn, is attached to the strainer housing which is the piece that holds your strainer basket and has the ports that the plumbing is connected to. The motor mounting bracket is attached to the strainer housing by either bolts or by a band clamp. You will need to undue the clamp or unscrew the bolts that hold the motor mounting bracket to the strainer housing.
  3. Now you can separate the motor with bracket from the strainer housing. When you separate these two, there may be a loose piece called the volute which covers the impeller. Sometimes the volute stays in the strainer housing, and sometimes it comes out with the motor.
  4. There will be a gasket or O-ring sealing between the motor mounting bracket and the strainer housing. Inspect this thoroughly and replace if necessary.
  1. Now, you can lift up the motor with bracket attached to get to the wiring more easily. There may be a bare copper ground wire attached to the outside of the motor that you will need to disconnect.
  2. Remove the cover plate on the back of the motor to get access to the wiring.
  3. You should have one green wire that is the ground wire and two other wires that are your leads. The lead wires should be black and white but could be any other color except green.
  4. Disconnect these wires (they may be attached to a screw, held down by a nut, or clipped on with a terminal clip).
  5. Next, you will need to disconnect the conduit (sleeve covering wires between motor and switch or junction box). This usually means unscrewing the compression nut that is screwed on the adaptor which is screwed to the motor. After unscrewing the conduit compression nut, you can pull out the wires from the motor. If you wish to reuse the adaptor, unscrew it from the motor.
  6. Now you must remove the impeller from the motor.
    1. Remove the volute covering the impeller if it is there (some are screwed on).
    2. You will need to go to the opposite end of the motor and pop off the plate covering the shaft.
    3. The shaft will either have a slot in it for a screw driver or is flattened to allow you to put an open end box wrench on it. This will allow you to unscrew the impeller.
    4. You will unscrew in the direction that is opposite to the direction that the veins point at the outside of the impeller. This is the same direction that the motor will rotate the impeller. This may look backward, but the water comes into the center of the impeller and rolls off the veins away from the impeller by centrifugal force.
    5. As you take the impeller off, be sure to note how the pump seal is positioned. We highly recommend replacing the pump seal when replacing the motor.
  1. Now you can see the bolts that hold the motor mounting bracket to the motor. Unbolt these, separating the motor mounting bracket from the motor.
  2. You are ready to reverse the process to install the new motor.

Important Notes on Motor Reassembly

  • DO NOT touch the ceramic faces of the seal; this may cause the seal to burn up and leak.
  • Be sure to tighten the impeller completely.
  • Be sure to wire the new motor for 110V or 220V depending on what you have. This may be a simple switch in the motor or you may need to use the wiring diagram on the motor to set the proper voltage (black tracer means the white wire with a black line corkscrewing around it).
  • Be sure to put the volute back on, aligning properly.
  • Be sure to reconnect the bare copper ground wire to the ground lug on the new motor.
  • When tightening bolts, alternate tightening a few turns at a time to seat evenly or the pump may leak.
  • Fill the strainer housing with water before starting the motor to prime ‚Äčthe system and prevent damage to seal and impeller.