How To Change the Thermal Overload Protector on an AO Smith Motor

This guide explains you where the Thermal Overload Protector is located on a typical AO Smith motor, and how to replace it.The Thermal Overload Protector on a motor monitors both motor temperature and current. When either exceeds the motor's limit, the Protector will shut the motor off until it cools. Overheating or high current are generally caused by other factors that overload the motor, like substituting the wrong motor or lack of proper ventilation around the motor. Occassionally, however, the Thermal Overload Protector goes bad and must be replaced.  This guide is specific to an AO Smith motor but many of the steps are applicable to other makes.

1. REMOVE ELECTRICAL COVER - Remove the two screws that secure the electrical cover on the electrical end of the motor. Lift off the cover.

2. LOCATE THERMAL OVERLOAD PROTECTOR - This picture shows the location of the Thermal Overload Protector within the electrical components of the motor.

3. DISCHARGE CAPACITOR - Pool Pump Capacitors store an electrical charge that can shock you even when the power is off. Before removing the capacitor, discharge this energy by placing a screwdriver across the leads of the capacitor. CAUTION: Capacitors have been known to explode when shorted out. For your protection wear eye protection and place a cloth over the capacitor before shorting it out.

4. PULL OFF CAPACITOR - Remove the single screw that secures a clip holding the capacitor. Note how the plastic strip is positioned between the clip and the capacitor. It will have to be replaced in this position to keep the capacitor from shorting out on the motor.

5. PULL YELLOW LEAD - Using a pair of needle nose pliers, remove the yellow wire to the Thermal Overload Protector from the capacitor.

6. REMOVE BLACK PLUG - The operational voltage is set by positioning the black plug so that its arrow lines up with either 230V or 115V. Note where the plug is set then lift the black plug off of the Terminal Board.

7. REMOVE BLACK WIRE FROM PLUG - The Black Plug is attached to two wires, one black, one white. Remove the black wire by sliding out its terminal clip from the Black Plug.

8. UNSCREW TERMNAL BOARD - Remove the two screws that secure the Terminal Board to the motor.

9. LIFT OUT TERMINAL BOARD - With the two screws removed, the Terminal Board should lift off the motor. Three wires are attached on its backside.

10. REMOVE BLUE WIRE FROM TERMINAL BOARD - Turn the Terminal Board over and, using a pair of needle nose pliers, remove the blue wire that goes to the Thermal Overload Protector.

11. REMOVE THERMAL OVERLOAD PROTECTOR - The Thermal Overload Protector is secured to the motor with one screw. The other end fits into a post. Remove the screw and lift off the Protector.

12. VIEW THERMAL OVERLOAD PROTECTOR - This is a picture of the Thermal Overload Protector with attached wires. If the Thermal Overload Protector does not come with the black plug, remove the white wire from the old plug and place the white wire from the new Protector into the old plug.

13. SECURE NEW THERMAL OVERLOAD PROTECTOR - Place the left side of the new Thermal Overload Protector against the post and secure the right side with a single screw.

14. ATTACH BLUE WIRE TO TERMINAL BOARD - Attach the blue wire from the new Thermal Overload Protector to the open terminal on the back side of the Terminal Board. Just push it on.

15. REATTACH TERMINAL BOARD - Turn the Terminal Board right side up and reattach it to the motor. Check that the wires passing under the Terminal Board are not pinched as you secure the Terminal Board.

16. ATTACH BLACK WIRE TO PLUG - Slide the clip at the end of the black wire into the open slot of the Black Plug.

17. REATTACH BLACK PLUG TO TERMINAL - Reattach the black plug. Line up the arrow on the plug in the same position noted in Step 6.

18. REATTACH YELLOW WIRE TO CAPACITOR - Reattach the yellow wire coming from the Protector to the open terminal alongside the other yellow wire terminal. It should just push on.

19. CLEAR YELLOW WIRE - Place the yellow wire on the left side of the post under the Capacitor so that it will not interfere with the spinning Governor.

20. ATTACH CAPACITOR - Replace the Capacitor and screw the holding bracket down with the single screw.

21. CHECK WIRE POSITIONS - Check that all wires are tucked in away from the spinning Governor.

22. REPLACE ELECTRICAL COVER - Replace the electrical cover at the rear of the motor and secure it with two screws.

If you have any other questions about pool and spa products please do let us know - we are here to help! 

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