Minifarmer,
I don't have any information for you about the vent pipe freezing. I would suggest calling Keith at Pond Dam Piping to see if he has any information.
Update on the siphon system. Due to recent strong rains, the pond has risen to within 8 feet of normal pool level. I decided I wanted to test the system out to see if everything is working properly. So me and my son borrowed a transfer pump from the farmer that built my pond and off we went.
This is a 5 hp pump that pumps about 50 gallons per minute or more.
After using some water bottles to float the intake pipe (so that it wouldn't suck up any rocks into the impeller), the pump was primed and the engine started. This is my son who is a great little helper.
This is the backside of the dam that is currently flooded. Man, I wish it were duck season already.
The pipe never filled up all the way with water because once the backslope pipe fills up, the water starts filling up the intake pipe. But because the intake is not shutoff, pressure pushes the water back out into the pond. So after running the pump for 20 minutes, I thought I'd give it a try. I replaced the vent cap and proceeded to open up the butterfly valve on the outlet. At first water came out pretty well, then a big roar of air, then a gusher. It probably shot water about 8 foot into the air. These pictures are from the top of the dam so everything looks small.
I ran it for about one minute, then I had my right-hand man to open the vent valve.
After 10 seconds of loud sucking noise, the water stopped.
My experience has taught me that it is probably better if you had some sort of vacuum pump to suck the air out because the pipe will never fill completely up with water by just pouring it in. Does anyone have a setup with a vacuum pump and some sort of safety valve/filter to prevent water being sucked up into the vacuum pump? If so, I would appreciate information on the vacuum pump (specs) and any pictures you may have of the setup.
