this happens to me all the time.
1 take the float off the bracket. (unscrew the elbow first)
2 pull the pin that holds the bulb part of the float the valve. (be careful there is a small piece inside that stops the flow)
3 take a pin or very small drill and clean the small orifice out. (mine gets plugged up there all the time)
4 put back together
the 90 degree pipe elbow that the ro tubing goes into. unscrew this and the jam nut and you can work on the float without the other stuff in the way.
the pin that the float pivots on is removable its just hard. push in on the pointed side of the pivot pin.
the hose from the pump goes into a 90 degree elbow, unscrew this from the float valve, (blue line first pic)
there is a jam nut and a set screw on the same side as the hose, (remove it red lines first pic)
the pin that the float pivots on is removable, push in on the pointed side it will take a lot of force but it will come out, (grey arrow in second picture)
there is a plunger inside that closes the valve, and a small hole, this small hole about 1/32 of an inch or so is what gets plugged up, you can not get to this hole with every thing together.