A somewhat less common problem with pumps can be that they are continuously turning on and off repeatedly. This can be result of several different causes. In this section, we will focus on whether the pump itself is the cause and how you can find out. You will need a multimeter for this step set to the AC voltage setting.
How to determine the cause?
1. Often a motor continuously cycling on and off repeatedly is not a failure in the motor itself. This can be caused by a bad relay on the circuit board of your spa control system, a failed main or auxiliary keypad, issues with incoming voltage to the spa, and a few other possibilities.
2. Start by removing the panelling that covers the equipment area on your hot tub.
3. Carefully remove the cover of your spa control pack.
4. 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
5. Test at the main terminal block with a multimeter. Confirm that your incoming power from the circuit breaker is steady and within range. (Fig.1)
6. If the main power tests properly, move on to testing voltage to the pump itself.
7. Engage the pump and test for voltage. 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. 2: Test Power to Pump Plug
Fig. 3: Test Power at The Motor
8. While testing, if the readings are jumping around going from high numbers and back down to zero, it’s a safe bet that your control system itself is the cause.
9. If power is steady to the pump, your motor is the cause. A full pump replacement is needed at this point. Be sure to check out our guide “Choosing the Right Spa Pump” for help in selecting the proper replacement.
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