This thread is for questions over a basic siphon to lower a pond level, not for level control. I.e. I have pvc stuck in the water, up the bank, across the dam and down the dam.
I'll try to make this as short as I can. Saturday I put a 4" PVC pipe into the water. A few inches in the water. 10 feet from that point up the bank, angled to a horizontal section across the top of the dam. The horizontal piece was also 10 feet long. A Tee in the middle to fill the system. Then 60 or 70 feet of pipe down the dam.
I held up the corner of the horizontal pipe, nearest to the pond with a spare 45* piece. That way I could fill more of the horizontal section, otherwise the water would run down to the pond and drain out. (I did note that the 45* elbow had fallen over at some point when the siphon started, so I don't know if I need that end elevated or not...maybe this is my issue)
Filled the system, closed the Tee, opened the cap at the bottom of the dam and away it went. It ran great for about 1 and a half days. Then the pond level got low enough to break the seal (I'm assuming, I didn't see it happen).
Fast forward to Monday. At the pond, I add a 22* elbow and a 5 foot section of pipe, to get into deeper water to drain the pond more. Filled the system the same as before, pull the plug and the water came out...but didn't get suction. Tried twice, rain out of daylight, gave up....super angry. I figured that there was to big of an air bubble with the 10 feet on the bank and 5 feet in the water.
Assuming that was the issue, today I removed the 5 foot section, and added a flap style check valve and a 3 foot section of pipe. I figured, this would allow me to fill all the way to the water line, almost no air in the system. Pulled the plug and the siphon took off! Ran for a few minutes, heard some bubbling and the water shut off. I have no clue what happened. This time I used a rubber connection, so I removed the valve and the 3 foot pipe.
I.e. Now I'm back to the same configuration that worked on Saturday. The only difference is there is less water above the pipe in the water than on Saturday. Filled the system (with the horizontal pipe elevated at the pond, so it was as full as possible). Pulled the cap and nothing, no siphon...again.
So what is going on? I'm not getting water leaking any any joints, so I know I'm okay there, I glued all of the joints. The cap on the tee is pretty darn tight. I'm removing the cap at the end of the system as fast as I can.
Do I need more water above the pipe for this to work correctly? I'm so confused and frustrated...especially since I'm filling by bucket and it takes about 16 buckets....By adding more pipe to the pond side (to go deeper in the water) I need more pipe on the dam side, right? 2-3 times more, right?
I'm just confused as to why I can't get this to restart. I really thought the check valve would do the trick...not sure what happened.
So....what am I doing wrong? Ideally this is a very simple system...why am I having so much trouble?
