272 grady waste system

[peter devine]

Help!! I have a overflow in my waste system. ( 1997 272 sailfish) I went out with a few children and found out they used paper towels to wipe themselves. The toilet paper is under the sink in the head and i can see that it is not in view so.... I took apart the entire starboard panels under the flybridge. There was waste pooling from the valve at the top. I am not sure how to describe the piece but it seems to be the highest point of the waste tubes and there is a metal pipe that forms an upside down U. at the top there is some type of rubber valve? What would happen if i close this valve and what can i do to stop this from spraying? Sorry for the long post but i dont know why or how this anti suction/valve decided to blow waste.
Thank you

 

[Grog]

It sounds like the anti-siphon valve. There may be a clog in the line from the anti-siphon valve to the holding tank. Is the holding tank full?

 

[peter devine]

Thank you for the response. The tank is empty. but when I use the handle to flush it spits into the starboard area under the aft berth. It was full and the pump boat sucked the head from the starboard deck plate. This was the first time I had the tank pumped. The next time I went out it was blowin urine and what ever :huh else from the ? not sure what to call it but it seems to be an anti siphon device. :huh

 

[georgemjr]

The problem I had was a clogged vent line. Without anywhere for the excess pressure to vent, I had difficulty flushing as the pressure built up in the holding tank. I would assume this could cause the valve to allow waste to spit out of it. I would check the vent line, it is easy enough to do. I now try not to fill the tank to full and check that air is being sucked into the line when I evacuate.