Shrieking Anti-Syphon Valve Heads Inlet Pipe

[KeelsonGraham]

Hi all,

For no apparent reason the anti-syphon valve on my Blakes head has started shrieking loudly when pumping in water. The bowl flushes Ok most of the time, but not always. And now, no clean water remains in it after the flush. I took the inlet pipe off the sea cock to test the inflow. There's some flow but it's not exactly gushing out. Could this be a blockage in the sea cock, or is it likely to be a problem with the anti-syphon valve itself?

[waughoo]

My first thought would be to check the duckbill valve on the siphon loop.  Many of them can be replaced without a whole new "loop".

[Jim Hardesty]

And now, no clean water remains in it after the flush.

With that symptom I think you need to change the joker valve.  It's a pretty clean job if done just after a pump out.
Jim

[KeelsonGraham]

Hi Jim, 'scuse my ignorance, but what is a joker valve?

[Jim Hardesty]

Hi Jim, 'scuse my ignorance, but what is a joker valve?

No, I envy you.  Never having to deal with a plugged joker valve.  Google "joker valve" and lots of youtube on how to change.  It's called a joker valve because it looks like a joker's hat, it's a one way valve that prevents back flow back into the toilet bowel. It's rubber and prone to deterioration and calcium buildup.  I carry a spare. 
Jim