I think the vent hole I was talking about is the vent pipe you described. Is the valve in vent pipe open(handle in the vertical position)?

How much fall is there from the highest point in the siphon pipe to the highest point on the outlet?


Is it possible to plug the outlet long enough to fill the entire pipe, expelling all the air from the system through the vent pipe?



"The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge." Stephen W. Hawking