Water inlet valve diaphragm operation

[MetalRocks]

I am investigating the cause for malfunction of a solenoid water inlet valve (when de-energized, the valve fails to close and instead exhibits cyclic surging of water flow). 4 of the 6 bleed holes are blocked with debris, and I have concluded that this is what caused the valve to malfunction However, I need to describe what exactly happens within the valve & diaphragm when bleed holes are blocked.

 

[Baluncore]

Please provide a section drawing or a link to the valve type you are using.

 

[MetalRocks]

solenoid valve diaphragm

I don't have a section diagram for this particular valve but http://en.wikipedia.org/wiki/Solenoid_valve has a pretty good general one. I attached 3 photos of the valve & diaphragm with the blocked holes indicated.