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?
I believe there is a limit to how many feet of head you can suck water. Suction style well pumps are limited to I think around 15 feet lift. Then you have to go to a pump element in the water.
How far is the dam above water level?
Looks like the theoretical limit to suck water is about 34 feet, or in other words one atmosphere (because the atmospheric pressure is what is pushing the water up the pipe if we could create a perfect vacuum within the pipe).
You are probably no where near that, but you may be far enough it is hard or near impossible to get enough vacuum to get the flow started. The slightest air pocket could be a problem.
lifting water A vacuum pump at the highest point in the pipe with proper valving might be the way to go.
My initial gut instinct is that you have air getting in when trying to use it. It may not leak out, but once you open it up and apply all that suction power, the smallest of air intakes will be your demise. Perhaps the first time you got it going it was fine, and developed a leak from use. Could the pipe have collapsed from the pressure the first time, when you did not see it stop, and that has caused a breach? Possibly just moving the pipe around a few times has broken a very small area of a joint open? Fill cap is sealed tightly?
There are many members here that are very good with siphons. Hopefully they will have some ideas.
How about trying it with a regular hose, just to see if you can get that going? A lot easier to work with for testing. Seems like if you could get that going, a bigger version would work.
I have about 10 feet of pipe on the rise. It was about ~5 feet of vertical rise from the water level to the top of the dam.
Should I put the check valve back on? Do I need more water ABOVE the pipe in the water, to get enough pressure going?
Fish n chips – I was wondering if I have an air leak anywhere, but I don’t know how I would determine that, short of putting glue over all of the joints on the outside of the pipe. The pipe should not have collapsed as it is sch 40 PVC.
The fill cap is pretty tight. I’m using a 3 foot wrench on it and getting it nice and snug before I go and open the cap at the bottom.
I could try a regular hose, but what would that accomplish? I had it running for almost 2 days, but then the water level got very close to the pipe inlet. I believe it sucked air.
I just can’t figure what I am doing wrong, right now, as to why it wont restart?
This is actually pretty simple. Tie both ends up as high as you can. Fill the pipe with water. Drop the pond end in the water. Take the lower end to the ground in a "J" (the "J" prevents it from drawing air back).
Now burp it. Go to the high point and lift it to waist level. Walk that hump down to the lower end, you will be able to feel it fill as you go. Don't go to fast, let it fill. Put that "J" back in.
As it runs there will be a gas build up at the high point. Just burp it again.
You can thank my Navy damage control training for that. We had a retired NASA engineer that worked on getting a siphon for four hours and failed, I did it in 1/2 hour.
Garryc -
Thank you for the reply!
Could you send me a message with some more detail. I have a general idea on what you are describing, however I believe I am lost in the details.
Thank you!
Matt
Heck Gary, reply here so everyone can benefit....
I'm a little confused on it too. Wouldn't dropping the one end into the pond first just let the water that's in the pipe flow out into the pond?
Cold- I have a big trash pump that I hook up with solid pipe and pull the water up 10' or so. I think the longer the lift, the more important a tight seal becomes. If I get the slightest air leak in one of the joints, it just don't work. Adding more glue to the outside never seems to fix it either. Its a tear apart/cut up and re-do type of thing. Hard thing to figure out where its leaking when your by yourself. Sometimes a liquid soap will help.
I agree, a little air leak and I'm SOL.
We got 1.25" of rain last night, I'm sure the pond level is back to normal.
I'm TEMPTED to try the system again...same setup as Saturday. The hill is already slick...can't imagine it now. I just don't feel that it will work. I'm by myself, so I'm hauling buckets, I don't have a pump available...impossible to check for air leaks
I don't know whether to try again tonight...leave it the same setup as saturday...at the check valve back in? etc
So frustrated.
The killer on a siphon is air. In cold's case he has a long drop to the bottom. What he needs to do is lay both ends of the pipe side by side above the water level with enough to allow the length of the pipe to fall in the water below the depth he wants to siphon to. The bulk of the pipe will be laying down the slope. After it's full drop the pond end in. As it falls the water will be exhausted out so no air can get in. Then go to the bottom of the loop and start pulling down the discharge end, always keeping the end pointed up, until you have a J at the bottom with the end a few feet above the loop. Then you burp it. You must have that J or P trap in it at the bottom. Just like the P trap in your sink prevents sewer gas from coming into your house, in this pipe it prevents air from getting in.
In this system there is always a little air at the high point. That acts to reduce the pipe capacity. When it is running below full capacity air gets in and breaks the siphon. With this P trap you put in, even if the pipe is flowing below full capacity the trap prevents air from getting in so it still flows.
Garry -
I have 70 feet down the dam, 10 feet across the dam and another 20 towards the pond. I don't see how I can do your method. I got lucky and it worked Saturday...but can't get it started again.
By adding that check valve at the water line, I thought I would have fixed the problem, as the entire pipe was full of water. However, I only have a straight section (threaded cap) at the outlet on the dam. The system ran for a few minutes, but then quit. I don't know if air got in from the dam side, or if I have a leak somewhere.
Without another trip to the hardware store, would adding a 45* to the outlet, then a cap, help?
In addition, I'm draining into a 100ft black corrugated pipe, to get the water off the dam. By adding a 45 or P trap, I'm not sure I'd be able to connect to the pipe.
would adding a 45* to the outlet, then a cap, help?
That might help, it's recommended in the following link.
http://www.ponddampiping.com/syphon1.html You say you have 70' of pipe on the backside of the dam, and 20' on the pond side, but are you certain that the discharge end of the pipe is actually at a lower elevation (4' or so) than is the intake end of the pipe? Looks can be deceiving on unleveled terrain, creating an optical illusion.
Also, I remember reading a thread where someone was using a wet-vac at the filler tee in order to remove the air, and fill the pipe before initiating the siphon. Sounds like a nifty trick.
Another thought: The check valve at the intake sounds like a good idea; however, I wonder if it may be restricting the flow so as to allow air to enter at the discharge end of the siphon pipe.
Cold-- I would try that 45. If I'm not mistaken, you will need to add a bit more pipe to that 45. You will want to make sure that the lowest part of the exit pipe(be it the 45, or an extension of more pipe) be higher than the highest point in the elbow that bends upward. Hope that description makes sense to you!
Also, depending on your type of check valve, make sure that before you start filling it, that it is free of debris that may be keeping it from closing. Had this happen to mine more than once.
Dumb luck or whatever you'd like to call it, I gave it ONE more try tonight. This time I elevated the elbow at the pond side more, so I had more slope across the top of the dam. I also tightened the #@*^ out of the Tee cap. 3 foot wrench on it and really leaned on it. Unscrewed the bottom and away she went!!! I should also note the water level is back to normal (Saturday level, when it worked last time) because we had a storm last night.
Now, I watched it flow for a bit, went back to the top, and there was a vortex forming on the top of the water, then it started sucking air down to the pipe.
I hurried up and attached a 4-5 foot piece of pipe (using a rubber boot) with a 45* angle facing down to the bottom of the pond. The straight section is clamped onto a slight angle, so this allowed me to get into deeper water.
However, still getting a small vortex. It wont be long, after it runs for a few hours or maybe a day and I'm sure it will air break. I don't know how to avoid this, short of running a 10ft instead of a 5 foot and angle it more into deeper water. I was trying to be careful not to hit the bottom but it drops off pretty quickly.
This also allowed me to figure out why the siphon STOPPED running after it ran for a day and a half. The first 24 hours or so, it was very windy out, choppy water, meant no vortex!! duh!! Monday, the winds died down and I think that's when the vortex formed and air broke the siphon. The water level was getting close to the inlet at that point.
I was just surprised to see a small vortex form, with that pipe probably over a foot deep in water, with an angled connection facing down.
I'll try to check it in the morning and see how it turns out.
I've got an anti-vortex plate on my trash rack for my vertical outlet pipe, works great.
But this siphon pipe is more horizontal. I guess the same theory applies?
I would think so. Can't hurt to try!
You don't really need any kind of valve with the P trap.
The issue is finding any of that 4 inch donkey dong that has absolutely no pin holes in it. One pin hole and it sucks air then fails eventually.
Then your math doesn't add up. Really you would need two 100 foot sections and some way to join them with absolutely no leaks. You are using a big chunk of 100 feet just getting over the damn.
Then there is building a simple eductor in the siphon line which enhances the flow. An eductor would fill the line and increase the flow.
Garry -
I got lost with this post, I was unable to follow it.
Let me try it this way. Draw an imaginary line at the water level through the dam. All the pipe above that line and all the way to the pond end is of negative value. All the pipe below that line is positive value. With the numbers you gave, there is no way you have any positive value on a 100 foot pipe. Really, I want to see a 3/1 ratio to the positive. That is 3 feet vertical down for every 1 foot vertical up. That means 200 feet in your case.
Here's a link to cold's pond. It has some pics of the dam. Perhaps this will help in seeing the scenario of grade. I think he has enough drop to get a siphon to work. Perhaps not all the way to the bottom of the pond, but he should be able to pull a lot of the water out.
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Main=28844&Number=370017#Post370017
As I remember a 3" ABS fitting fits snugly inside that 4" donkey dong. If you could get it glued together and seal making this siphon is simple.
Garry –
Sorry, got busy at work and couldn’t check this…
I probably have 45 feet of negative value and 70 feet of positive. Sounds like I’m right on the edge of it work. However, I was able to get it working last night.
My concern now is that the pipe is getting a vortex to the water and slowly sucking in air (we don’t have much wind right now). How do I avoid that with a horizontal pipe? I know of an anti-vortex for a vertical pipe…I don’t know if it works for horizontal as well?
My goal is to let this siphon run until it sucks air and breaks, then add more pipe on the pond side, under water, going to the deep section of the pond. I am hoping if I get the pipe deeper, I will have less chance of a vortex. But it sounds like I might need to add more PVC to the dam side for more suction.
I thought 3/1 was the ratio, and that’s what It was originally made at. However, I was counting the run across the top of the dam. I am able to fill most of that with water and it is sloped towards the dam, so it should be adding suction. I’m probably around a 2.5/1 ratio at the moment.
Your ratio is of as all that counts is what is below the water line. The end of the pipe must be deep enough not to have a vortex. The only thing I can think of to stop that is an elbow pointed down.
Let me explain my thought. IF you can get the 4" donkey dong to glue to the 3" fitting (it will go over the outside of the bell) and get it to seal. What I would do is glue it deep so the end of the pipe comes past the bell section, then I would pour glue in the grove and let it dry. Put a T in the middle at your high point wit a 4 foot stub pointed up. Glue a coupling on both ends and put on threaded caps.
From the top of the T have a pipe sticking straight up about 4 feet. Fill the system from the vertical pipe. when the water is near the top of that glue on a cap. Glue the pipe and the cap, you should see a bead form as you slip it on. That pipe is your air trap now.
Go to the pond end and keeping the pipe under water, remove the threaded cap. Go to the bottom and pull you P trap in, then remove the cap. You may have to tie a concrete block to it to maintain the P trap.
As far as where the pond end is, put it in deep. Take a yard stick and walk out and drive it into the mud. Count how much time it takes to drop an inch, then you can about figure when you need to check it again.
Break the siphon, just cut the cap off.
I currently have an elbow pointed down on the pipe. Still getting a vortex. I'd say the pipe is at least 12" under water. Hard to tell with the refraction.
I'm gonna' weigh in with a hillbilly method.....we used to drain the HBG pond every year, using rigid, 4" pvc pipe. Our setup sounds very similar to what cold is describing, with the exception that we didn't glue all the joints. We needed to be able to disassemble the contraption and store it, between uses. That's hard to do with a 70' piece of pipe.
The joints that we didn't glue, we simply wrapped tightly with Saran wrap. Don't laugh, it worked for years.
We ran a 3' piece of 2" pipe off of a T, placed where the vertical section coming out of the pond met the horizontal section going across the dam. The 2" pipe contained a valve, was capped on the end, and a barbed hose fitting of about 1/4" or so was threaded into the cap. To start the siphon we used an engine cleaning wand....the kind that attaches to compressed air and has a suction hose to apply detergent. We used a gasoline powered air comp. to provide the pressure.
To cap off the pipe on the downhill side, we jammed in 2 liter soda bottles. As I recall, they were a near perfect fit. We did wrap that joint in Saran wrap also however. A quick cut with a pocket knife and that bottle would come flying out once the pipe was filled.
To start the siphon, we hooked the wand's detergent hose to the barbed fitting, connected the air comp. to the wand, fired up the comp, and just squeezed the trigger on the gun. When water sprayed out of the wand's tip, the pipe was full. Close the valve, uncork the bottom, and away it went. It took longer to tell about it than it did to do it. We actually loaned this setup out to a couple of other folks who wanted to drain their ponds down.
By the way...trying to feed rigid lengths of 4" pvc out into deeper water can be difficult, as the pipe tries to sink to the bottom and gets very heavy. Capping that end with a soda bottle will make the job much easier, provided someone is willing to go out there and remove the bottle and allow the pipe to sink, once in position.
Very ingenious, Sparky-I've done the same with 3", minus the Saran wrap...
I am seriously starting to worry about your self esteem, however.
Good plan. Lets adapt it to the donkey dong. Fill t with water with the seam sideways. Locate any leaks and wrap them with shrink wrap. Glue the fittings in and also wrap them with shrink
wrap.