Yes we removed the jumper between J28 and J57, installed the black jumper on J11, and moved #10 dip switch to off (for 50 amp service). The tech from Balboa, the company who made the parts, said that line 1 and neutral coming into the spa supply the 120v to the pump. But the pump connection has 4 wires -- black, red, white and green. The system is supposed to change the 120 V from the black wire to the 120 v from the red wire when the pump is switched to high speed. It almost seems like the pump might be getting 240v when it switches to high speed, which would trip the GFCI.