Ask 'Dr. Spa' Q & A Message Board

: I have a single pump Freeflow 120v spa. Everything works fine until I
: switch the tub to high speed. Then the GFCI trips immediatly. Not the
: breaker itself, but the gfci function. Since it runs fine on low
: speed with the heater running and the heater shuts off when switching
: to high speed since it is a 120V...does that mean it is definitly the
: motor that is the problem? I have gone from low to high with the
: heater off completly and same issue occurs. I am an experienced
: residential electrician, but I do not have much knowledge with
: electric pumps and spas.

Disconnect and isolate the motor conductors. Use a megger to ohm across from ground to each current carrying conductor. Any reading on the megger indicates the problem is in the motor, either a pump leak or motor winding issues.

John