Hello all, I have ran into a slight problem with a jacuzzi j-315 it is a 2004 model. I am getting the dreaded FL-1 error and it is driving me nuts. The main pump works in both speeds. I have ran the hose back through the heat wall spot to eliminate the "air lock," that did not work. My main question really is, the two water filters, one nearest the control panel in particular, what kind of circulation is supposed to be there? I can pull both filters off but the one furthest from the control panel is the only one that has any suction. There is one more thing also, i pulled the flow sensor plug off of the board and put a jumper in to "close" the circut, and the heater kicked on correctly. But with the switch plugged in the switch is keeping the circut "open." Could this mean that it is the flow switch? And also, is there another pump to control just the smaller jets at the "feet" of the occupant. If there are anymore questions you need answered just reply.