Pond Boss Forums INTRO Questions & Observations Syphon System Problem

I have a 3 acre lake in which I replaced an old overflow pipe with a syphon overflow system sold by Pond Dam Piping. You can see a diagram of this type of system at http://www.ponddampiping.com/syphon1.html

Twice in the last 6 months the syphon has failed to stop when it should resulting in a drawdown. One time was caused by a clog in the air vent pipe. The other time there was no clog in the air vent pipe. Pond Dam Piping suggests I place a wire across the air vent pipe to prevent trash from entering the vent.

Has anyone else had this problem and if so what solutions have you found? Thanks

Frank

Frank,

one easy way to fix the problem is to buy a 180° fitting, a short piece of 2 inch pipe (or what ever diameter pipe your air breaker is made of) and an end cap. drill a bunch of holes in the 2 inch pipe and end cap then shove it on the air break. if you dont glue it on you can remove it if it gets clogged. make sure you clean it often so it does not get stopped up.

I have fixed a few siphons this way.

You could put a valve on the outlet side. In my pond I run the outflow through a pump/pressure tank for irrigation. I don't have a breather so clogging is not an issue for me. My problem tends to be the reverse, too much draw breaks the siphon and I then have to recharge the pipe (about 1/4 mile). Just a thought.
Jim

Frank,
I have not had the problem that you have had, but I seem to have a problem in that my system will not syphon. We have had major storms in the last couple of months and I don't think that the syphon has ever worked. I assume that we have an air leak in the air vent pipe, but does anyone have any other thoughts as to the problem that I have had?

bdoug,

check to see if your intake is packed with leaves. I have seen several siphons that get clogged at the end with debris. they work fine its just clogged at the end. the hard part is getting down to the intake (underwater) I once had to hire a diver to go and check it out. he used a leaf rake to get the leaves and trash off the intake screen and the siphon worked just fine after

if you have an air leak you can hear it even under ground, sounds kind of like a leaking tire

it also helps if the siphon is turned up at the end, putting a 45° or 90° at the end of the pipe will keep air from running up the back side and breaking the siphon

just some thoughts

You might want to increase the size of your air/vent/fill pipe. What size pipes are you using? Of course since its being sold as a working system, you'd think it would come with whatever pieces it needed to help prevent clogging and all be of a proper side.

Perhaps an atrium type device, as mentioned below on the end of the air/vent pipe would help prevent it from becoming clogged. With multiple sides open on the little atrium, there is less of a chance that all of them would become clogged at once. It may depend on the size of the pipe you are using as to whether a premade one that size would exist. If you keep having problems, I really would like to know before I add this piece onto my system. And if you solve the problem, let us know what worked for you.

I built a 4" PVC pipe siphon based off of this diagram myself this past fall for my 1.5 acre pond. I haven't added the air/vent portion yet and just have it open up top, used a simple end cap that the suction kept pulled down.

I did make two modifications:

First, I put a 90 deg elbow on the end of the intake pipe and attached an atrim to the end of that to get it up off the bottom and preventing it from becoming clogged with mud and other bottom debris.

I also modified the point where it comes out of the pond to the 1st 22 1/2 deg elbow. I brought it up about 4 inches higher and put a 45 deg elbow, about a 4" pvc piece into a 22 1/2 deg elbow into the main top pipe, creating a little hump right before it transitions under the air/vent/fill pipe, into and out the back side of the dam. The main reason I put this hump/bump in, was so that when I primed this siphon pipe, I would fill up the entire pipe including the flat portion accross the top, giving me about 14 more feet of pipe full of water. After making this modification, getting the siphon started was always successful, even with the water level down 5 feet or so.

I also left the joint from the pipe coming into the 45 deg elbow unglued and only secured it with duct tape. I can easily pull up the pipe from the water and check the end.

On another note, on the outflow end, be sure to put the extra pipe to angle the outflow back up, as shan mentioned, this will help prevent the air from being sucked back up into the pipe. (Very important) Also, for the other people like me out there, I didn't think it through the first time and tried to put a simple end cap on the outflow :rolleyes: Of course it popped off after about 20 gallons or so on it, even with duct tape. I smartened up and got a screw end cap. Another hint here, don't screw the end cap in very far. Once you fill the pipe, you have to push in on the end cap and unscrew it at the same time. There is alot of pressure on that thing

Frank
I had a similar problem with my 3 acre pond 2 weeks ago. The water level had dropped about 5 inches below the air vent pipe when i discovered it. My air vent pipe has a heavy metal screen with 1/4" holes, but obviously had sucked in some filamentaeous algea/leaves/trash enough to block the air from breaking the siphon. When the siphon was installed, I poured a small concrete pad about 3 inches below the air vent pipe along with a piece of flat granite at a 90 degree angle on the back edge to hold back the dirt. In an effort to prevent a reoccurrence of the problem, I used a plastic flower pot (dark green), cut a hole in the bottom large enough for the air vent pipe to enter, bored 8 holes with a hole saw (5/8") near the top of the pot, inserted the air vent pipe into the bottom of the pot and placed the flower pot upside down on the concrete pad.