R/O and float valve

I've got a pinnacle R/O unit that I have had for a few years. It comes with a solenoid in the tubing that allows you to hook up a float valve that will shut it off.

Recently mine has not been shutting off completly and it is causing the 50 gallon drum to overflow.

Anyone ever trouble shoot anthing like this before? The float valve can't go bad, it still floats. I thought that it might be from my outside water shutting off on timers causing the water pressur to jump, but I didn't water for a week and it happened. Can these solenoids go bad? Any input would be greatly appreciated.

 

You say Solenoid ? are you referring to a little 1' square white block that has a tube from the R/O housing to the filter outlet ? If so thats a auto cut off and they suck it has 3 ports on it and 4 screws with a rubber like gasket in the center ? What that does is when the float shuts off the pressure increases on top then that pushed the diaphragm and plunger onto a seat facing to stop the waste water flow . The better units are white with 4 ports and are made with ridges all over them they are a far far better design . Can you send me a Photo or post one here ? But I think thats what you have ?