I have several 3/4" Toro Flo Pro irrigation valves which I use to control a drip irrigation system. Recently, one valve has failed to close when its turn to water is over. I was told that the only thing that fails is the diaphragm. Clean it first, then replace it. Cleaning, followed by the installation of a replacement diaphragm had no impact on the problem.

By swapping parts between the two valves, I've concluded that the problem is that one solenoid is not closing properly. The solenoid appears to be a 'no service' unit. That it is filled with water appears to be normal; am I correct? It appears that it functions by lifting a flap from the "Seat Assy., Discharge" (part key #7, 89-0069) in the diagram for the "Flo-Pro Series, 3â4 and 1 Inch AVB" in the link given below, which is a blow-up of the parts for this automatic vacuum breaker control valve.

http://www.lljohnson.com/Documents/rescom%20literature/Toro/Valves/Flo%20Pro%20Anti%20Siphon%20Installation%20Guide.pdf

I tried activating a good solenoid with power from the controller and comparing it with the bad solenoid. Clearly the good one closed and opened reliably. The bad one hung up in the open position. It is not clear to me if the closing of the flap is spring driven or gravity driven. I lubricated the bad one with a few drops of high temperature or phenyl-methyl-silicone oil and activated it through many cycles. It seems to be working for the time being.

Has anyone else any observations regarding these solenoids?

Thanks,

baumgrenze