A very common problem in hot tubs is the pump will simply not turn on. The causes are generally electrical in nature but not always. It’s possible the pump motor has power, but the motor is seized. The cause could also be an obstruction inside the wet end, resulting in the impeller being unable to spin.
The control system could also be the cause, perhaps it is not providing the proper voltage to the motor.
How to determine the cause?
1. Start by removing the paneling that covers the equipment area of your hot tub.
2. Engage the pump at the keypad if possible.
3. Be sure an indicator is present showing your spa control system acknowledges that a call for the pump to turn on has been initiated. (led light or screen icon)
4. Carefully remove the cover of your spa control pack.
5. It is important to rule out any issues with the main incoming power before moving to the next steps.
Fig. 1 - Test Power (spa control pack)...
... at Main Terminal Block
6. Test at the main terminal block of your spa control system with a multimeter. Confirm that your incoming power from the circuit breaker is steady and within range. (Fig.1)
Fig. 2: Test Power to Pump Plug
7. If the main power tests properly, move on to testing voltage to the pump itself. Power to the pump can be tested at the receptacle where the pump plug attaches (Fig.2), or at the back of the motor (Fig.3)
Fig. 3: Test Power at The Motor
8. A seemingly non-working pump can be attempting to run. Listen for a hum or other noise.
9. If the motor is humming, shut down power to the spa and attempt to manually rotate the shaft. The shaft can be located at the back of the motor or between wet end / motor on some models.
10. If the shaft rotates freely, but will not spin on its own under power, a bad motor capacitor (Fig.4) or other internal motor damage could be the cause. You can try to replace the capacitor or bring the motor to a repair shop, but generally installing a new pump/motor is a much better repair.
Fig. 4: Examples of Motor Capacitors
11. If power to the spa is off, you attempt to manually spin the shaft, and it is stuck or hard to move, you may have internal damage to the wet end, an obstruction, or damage to the motor.
12. Inspect the interior of the wet end.
13. Turn off circuit breaker to the spa.
14. Shut isolation valves or drain the spa.
15. Disconnect the pump (See “Pump Installation Tips” for detailed instructions.)
16. Leave the pump in place if you have ample room to work. If you do not have enough space, remove the pump from the spa cabinet.
Fig. 5: Remove Wet End Cover
17. Using a screwdriver, remove all screws around the diameter of the wet end. (Fig.5)
18. Pull off the intake cover and set aside.
19. Inspect the inside of the wet end for damage/obstructions.
20. If no damage exists, most likely the motor is seized internally. Replace the pump. (See “Choosing the Right Spa Pump”) if you need help learning what information you need, to be sure your replacement is the correct one.
Tech Tip 1
If your pump is over 10 years old, it’s better to replace the whole pump and motor if you are having problems with it.
Tech Tip 2
When purchasing a new pump, it includes a warranty from the manufacturer.
Tech Tip 3
Changing parts only can be a frustrating experience. Often older models are not compatible with newer available parts.
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