Originally Posted By: gully washer
Originally Posted By: Lynyrd
I made a couple of small mistakes on the siphon. It did not come on by itself. In fact, it was vapor locked and would not let any water through at all. I had to bleed the air pressure off of it before it would start. But, I know what I need to do to fix it so that it will self prime, and it won't be a hard fix.
Hello Lynyrd........... I'm curious as to what the problem with the siphon was. Was the high point vent clogged, or was the vent pipe routed too deep into the pond? I'm thinking that vapor lock shouldn't occur in an open ended siphon overflow regardless of whether or not the vent is working, but after looking at your pictures I did notice the long length of riser pipe at the discharge end of the siphon. Depending on piping elevations, I'm guessing that this long length of riser might possibly create enough head pressure at the outlet so as to allow an airlock to occur at certain pool elevations, should the high point vent become clogged.............. Just a thought. Like I said, I'm curious.

btw: NICE project, and congrats on the rain.


I originally had the air vent pipe too low in the water. My idea was that I wanted the siphon to continue to run until it had draw the water down to just below the bottom of the main pipe going through the dam. As the pipe filled with water, and as you noted because of the 6 foot extension on the outlet side of the pipe, air could not get out either the vent, or the bottom of the siphon. I had to open the primer cap to vent the air. There was quite a bit of pressure in there when I pulled the cap off.

I have since raised the level of the intake on the vent pipe. I don't know where it needs to wind up yet. The lake has not risen high enough in the last month to make the siphon kick on. The 12" pipe is handling the normal water flow.

I've got a picture somewhere of my new set up, but what I did was add an adjustable pipe underneath the air vent pipe. This will allow me to fine tune the height of the air vent.


Just an old guy who likes to fish.