Silent and Failsafe Overflow System

[Floyd R Turbo]

as long as your holes are 6.5" apart, you can use the P traps. That's for lining them up in a straight line. If your box is a little wider, you can rotate the pieces and the holes can be closer. Also the siphon is really the only line that has to have 6.5" to another hole, and that's only so that you can insert a piece of pipe into the intake to get it close to the bottom of the box (you you want to) without conflicting with the adjacent bulkhead flange.

You could also have all 3 holes tight together and the E in the middle with the OC and S on either side, pointing sideways.

The p-trap is in the DWV section of Lowes

looks like this

http://www.lowes.com/pd_23433-1814-PVC+00707X+0600_0__?productId=3132849

 

[uncleof6]

Thanks for confirming that Floyd

Thats actually how i first started but i thought it would make everything too high and not work.

Looking at the pics do you think i can fit the p-traps in there? One hole is kinda offset from the other 2

The bulkheads are 1.5''

The inside of the box is 27.25''

We need to stop right here, and go back to the beginning. You are fixing to change the whole drain system for a problem that is simply caused by one of three things: The air vent line too low in the overflow, (the most obvious problem in your original photos,) the outlets to the drain lines are too deep in the sump, > 1", (second most obvious problem) or three, the bulkheads are too large for the flow rate. Generally you do not need 1.5" bulkheads for a flow rate under ~ 2000gph. If the flow rate is too low enough, 1.5" bulkheads will not back up the water level enough in the overflow to start the siphon. Invariably, every time this starting issue comes up, it is one of those three things. Only the later requires modifications to the system, the other two just need corrected.

There are no mysterious issues that need to be chased around in circles, and the top end plumbing configuration has nothing to do with your starting issue. As far as the tees on the top end, they have nothing to do with either the function, or the sealing of the system (if all external.) The tees and caps as simply a service access: Unscrew a cap, run a bottle brush through the drain line from top to bottom, put the cap back on. Pretty simple. With well over 250 of these systems running I have yet to run across a single problem with this system related to the tees and caps, well unless you don't seal the cap properly. Nor I have had and problem with the height relationship between the siphon and the dry emergency. The raising of the open channel inlet by 1/2" is a quick fix for the over-sized bulkhead issue, if that is the issue involved. People just don't think about this sort of thing, so attribute such in ways that seem to make sense, making things more complicated than they need to be.

This system works as designed. Your implementation is "as designed" save for the bulkheads being under the tees, rather than before the tee. Floyd's system is not a BA as designed, it is heavily modified, and it will not work the same as a BA, therefore the setup needs to be different, to achieve the proper function. The 'p' trap open channel cannot be at the same level as the siphon, other wise the open channel would trip to siphon during start up, and the siphon would not start—which is one of the causes for your issue. This system worked on the original design, and every other properly implemented system, with the elbows at the same level.

You don't need to change the configuration of the drain top ends. But looking it at, I think the top ends need to come up higher in the overflow. You have a pretty long waterfall into the overflow. You need to sort out the errors made, if any, and get it adjusted properly.

Your issue with the return section running dry is because there is not enough water in the system. Water in will always equal water out. If water goes up to the tank, and does not drain down and fill the return section again (after going through other sections) where is the water going? If it is not going down the drain, it would be flooding the floor. If you don't have enough water in the system in the first place, the drain system will not start anyway. Therefore you need more water in the system.

Those are the problems with this system.

 

[Floyd R Turbo]

I don't know that I agree that my layout is "heavily modified", it's the exact same basic principles. And it does work the same...I can testify that it works the same after having a big snail go down the siphon line while I was working on the tank!!

I do see what you mean about there being no requirement for level differences between the OC and the siphon though, because the only way the OC can kick in as a siphon is when the water reaches the level of the airline. Otherwise air wil intrude and generally prevent a full siphon. With the p-trap, the only difference is where the air inlet is, and you can put a JG fitting on the cap or just use one without the screw cap and tap a hole for the JG fitting and it works just fine with the airline method.

I also agree with the pipe size, that's a good catch. To fix that I think you can just downsize the pipe below the bulkhead to 1" with a reducer and that will allow the siphon line to close off faster and match the flow you are running. Then leave the rest as 1.5" as that doesn't hurt anything.

Also I didn't notice the airline was so low - hard to see in the pics or maybe i just wasn't looking close enough.

As usual, the simple answer is usually the right one. Sorry if my complicated take on it caused you to do more work than required!!!

 

[ChrisQ]

well, i just got back from my LFS and Lowes and im glad i checked this before i started cutting the bulkheads out but i must say, im still confused as always.

I'm in the process of draining the tank of fresh water should i just stop where im at and regroup again?

I bought new bulkheads and p-traps but if i dont have to change them then the better

 

[uncleof6]

I don't know that I agree that my layout is "heavily modified", it's the exact same basic principles. And it does work the same...I can testify that it works the same after having a big snail go down the siphon line while I was working on the tank!!

I do see what you mean about there being no requirement for level differences between the OC and the siphon though, because the only way the OC can kick in as a siphon is when the water reaches the level of the airline. Otherwise air wil intrude and generally prevent a full siphon. With the p-trap, the only difference is where the air inlet is, and you can put a JG fitting on the cap or just use one without the screw cap and tap a hole for the JG fitting and it works just fine with the airline method.

I also agree with the pipe size, that's a good catch. To fix that I think you can just downsize the pipe below the bulkhead to 1" with a reducer and that will allow the siphon line to close off faster and match the flow you are running. Then leave the rest as 1.5" as that doesn't hurt anything.

Also I didn't notice the airline was so low - hard to see in the pics or maybe i just wasn't looking close enough.

As usual, the simple answer is usually the right one. Sorry if my complicated take on it caused you to do more work than required!!!

I have no doubts that your design works, pretty clever actually. It needs a slightly different set up (height difference) to work. I don't see any reason that it would not. Since no two systems are alike, my only thing would be head height needed to start the siphon. Given enough vertical room, that could be tweaked. Hence the "pet peeve" about shoe horning into small boxes. Perhaps heavily modified is the wrong descriptor. Perhaps variant would have been better.

Occam's Razor is written all over BA's design. Since the original design works, and works repetitively time and again, I/we tend to look at what is different with a "problem" system. Fix that, and the problem usually clears. The list of potential problems is very short, and finite. Keep it simple. The only "problem," so far, that was not so easily resolved is the bulkhead size/flow rate, but the quick fix is bush the siphon to 1". (In some cases 1.25" would work.) But for that to work, everything else has to be "right." I have some suspicions concerning some "small box syndromes" but nothing I can make a case on yet.

 

[Floyd R Turbo]

well, i just got back from my LFS and Lowes and im glad i checked this before i started cutting the bulkheads out but i must say, im still confused as always.

I'm in the process of draining the tank of fresh water should i just stop where im at and regroup again?

I bought new bulkheads and p-traps but if i dont have to change them then the better

I would start by taking Uncle's advice and fis the two simplest issue first - cut the pipes in the sump to 1" under the water line (easy), move the airline all the way up on the E drain (easy) and swap out the siphon plumbing for 1" (not as easy)

Then try it out. With a reduction in necessary water volume to fill up the 1" siphon line, this may solve the water volume issue...

 

[ChrisQ]

I would start by taking Uncle's advice and fis the two simplest issue first - cut the pipes in the sump to 1" under the water line (easy), move the airline all the way up on the E drain (easy) and swap out the siphon plumbing for 1" (not as easy)

Then try it out. With a reduction in necessary water volume to fill up the 1" siphon line, this may solve the water volume issue...

sounds good, i'll give it a go, haha too bad i just drained the tank and sump but i did just buy some pvc cutters so that should make it easier if i can cut it in place.


If i can get it running with the water in the box just at the top of the elbows for long enough is it safe to say that will be the "running water level" for the drains in the sump? I'm trying to figure out how best to accurately cut the drains.

 

[Floyd R Turbo]

I have some suspicions concerning some "small box syndromes" but nothing I can make a case on yet.

Just thinking about this - I did some calculations after talking to bean about the external box on a high flow system.

What I figured is the rate of rise of water in the box based on the footprint of the external box and the influent water flow rate. This actually cause me to make the external box larger for a system running a higher flow rate.

One thing that I had to take into consideration was the relative level of the external box. For a rimmed tank, you have to put spacers on the box to allow it to clear the trim and be level with the tank. Otherwise, the top of the box is below the trim and this can set you up for an issue. Say the siphon line clogs and the water starts to rise. If the E and OC kick in fast enough, you're fine. If not, the external box can overflow if it is built too shallow.

With the external box even with the top of the tank the water level in the box will rise quickly, but when it reaches the water level in the tank, it will slow because the tank water level is now rising with it. With the E drain 2" from the top of the box, this allows plenty of time for it to kick in and take on the excess flow not taken up by the OC before it kicks in. With the P trap hole open (plug removed) as soon as you get a good amount of water over it, that will quickly purge and flush, then the process will repeat (as the OC is not tuned, it will likely cause a cyclic flushing)

So the issue of the small box must be accounted for by total water volume of the box, i.e. height. This can also be done by making the box deeper, and putting the plumbing down low, but this is really hard to do because placing pass-thru bulkheads higher relative to the operating water level required with such a setup means the water is crashing out of them into the box and this doesn't work. I know this from experience. The result is that you have a deep box with high bulkheads and the timing of the water level rise to a level necessary for the start-up process to happen and result in quiet operation is too fast, and the box overflows. I'll let you guess at how I found that out.

The pass-thru bulkheads must be underwater for the system to be silent and have a bubble free operation on the siphon line in the sump. This generally means you have to have the external box tall enough to cover the necessary rate of rise, which means it has to have the top even with the rim of the tank.

 

[ChrisQ]

oh btw, the air line was just a hair under the bottom of the cap. Was that too low?

 

[Floyd R Turbo]

sounds good, i'll give it a go, haha too bad i just drained the tank and sump but i did just buy some pvc cutters so that should make it easier if i can cut it in place.


If i can get it running with the water in the box just at the top of the elbows for long enough is it safe to say that will be the "running water level" for the drains in the sump? I'm trying to figure out how best to accurately cut the drains.

I'm not sure I'm following you.

The other thing that you will want to do while you are replacing the siphon line is to put the gate valve at the lowest point possible. A long vertical run under the gate valve will let the water free-fall and could be letting air intrude or rather prevent air from quickly purging out. This also causes a long start-up cycle.

 

[Floyd R Turbo]

oh btw, the air line was just a hair under the bottom of the cap. Was that too low?

I believe you want the airline to be just below the maximum water level that you want in the DT.

So if you have a desired water level of say 3/4" from the rim, put it at 1" below the rim (1/4" below the maximum). So when the water level in the tank starts to get to the point where it will start rising, that's your "oh-cr-p" point and you want the OC to convert to a siphon before that happens.

But check the OP just to make sure....or Uncle will correct me

 

[uncleof6]

Air vent line should be attached just below the trim lip inside the tank. Look back through a few pages, and you will find an image that shows said lip. Trying to translate that to an external box could be a bit tricky. Again, it is not rocket science, you just don't want it occluded during start up, ever, but you want it to trip before the tank/external box starts overflowing, (with some wiggle room,) which ever would occur first.

Easy way to set it, is to run the system without it, until you get the system up and running properly. Then when you restart it, note the high water level and set the air vent line inlet a little above that.

 

[Floyd R Turbo]

you just don't want it occluded during start up, ever,

Never caught this, but in the one I set up I just snaked the airline down the emergency drain. It stablizes so fast though, and since I have the OC about 1" higher than the siphon, even if it does kick over to siphon it won't suck the box dry which allows the siphon to continue purging and the OC opens back up again.

Uncle can you see a potential issue with doing it like that?

 

[uncleof6]

Yes I can see it occluding before the siphon purges. Water should flow in the dry emergency during start up. (Usually anyway, every system is different to a point.)

 

[thejuggernaut]

Yes...glad you agree. I think that additional plumbing is the cause of the problem. If the system isn't really high flow, then the water going through the siphon line is not going to be turbulent enough to churn all that air up and suck it out. So the result is that you have an airlock type of situation, and in order to resolve that the water level has to rise higher relative to the air bubble and compress it to get more water to flow. The more water flows, the more the bubble is purged, the more water flows, and the effect cascades until all the air is vacuumed out of the siphon line.

The other problem I see is that the OC is very close to the level of the siphon line, when looking at the horizontal cross-section of the pipe for both of these relative to each other. You don't need these to be close, you don't want these to be close. You want the siphon line in the bottom of the box, as low as it can go because it doesn't control the the operating water level of the box. The OC does. So IMO the horizontal center of the OC must be no lower than the top of the siphon elbow in order to work right. If you have the space, higher.

I made this, if this helps visually explain what I'm trying to describe

Why even put a p-trap on the submerged line. I ran one without it for years and honestly I never understood why anyone puts one on it. Mine never surges when starting back up. The water level just slowly rises to the open line. Maybe I am missing something.

 

[adova]

Good morning all!

I cranked up my new system for the first time last night and I need a little help troubleshooting my drains. My problem is that I am getting some "running water" noise from the gate valve on the full siphon line. Everything is glued except the connection into the male adapted that is screwed into the bulkhead.

I have some theories as to what may be wrong, but I wanted to check before i start chasing fixes if they are not related:

My siphon line is too high in the overflow. Just made some poor calculations here. I can switch to slip bulkheads and reduce the height significantly.

The gate valve for the 2nd drain is full open - I only adjust the main siphon. I realize now that I did not need the extra gate valve, but whatcha gonna do

The main siphon line runs straight into the sump. It is submerged about 2 inches. I realize that 1/2" is optimal (just did not pull it yet). Could this be the culprit?

Thanks in advance!

Shawn

 

[adova]

Here is a quick vid - it doesn't sound as loud in the video, but I swear it is, lol.

http://youtu.be/JubuTYv8YaU

 

[Floyd R Turbo]

Yes I can see it occluding before the siphon purges. Water should flow in the dry emergency during start up. (Usually anyway, every system is different to a point.)

Well as I mentioned, the OC is about 1" above the siphon, so even if it does occlude the opening fully on start-up, it doesn't drain the box down to the point where the siphon line opens up so it doesn't interfere with start-up.

Now that I understand that you can run the OC and Siphon at the same level, I can see how this variant is different though.

Why even put a p-trap on the submerged line. I ran one without it for years and honestly I never understood why anyone puts one on it. Mine never surges when starting back up. The water level just slowly rises to the open line. Maybe I am missing something.

If you do the original design (internal box only) then no, you wouldn't need a P trap, just a downturned elbow. But with all the plumbing in an external box (variant design) and the bulkhead in the bottom of the box, you need to have a 180 elbow hence a P trap or 2 90s together so that the siphon intake faces down. Otherwise it would face sideways.

 

[Floyd R Turbo]

My siphon line is too high in the overflow. Just made some poor calculations here. I can switch to slip bulkheads and reduce the height significantly.

I don't think you need to switch bulkheads, but you could. this falls under the variant design (external box, bottom bulkheads). Should we start calling it that?

So you could friction fit a P trap into the thread/slip fitting and reduce the height a little, but not much. With the external box you don't need the cap for cleaning access, you can just remove the plumbing part (For reference, 3 years and I haven't had to do this yet).

What you could do is cut the slip side of the fitting down bit so that the double-elbow can be lower in the box. Again it doesn't have to be water-tight but does need to be air tight (so seal with TFE paste is fine) because the siphon line can pull air in through a loose joint (resulting in air in the sump outlet, not a big deal, just an annoyance)

Or, you could change the BH to slip on flange and friction fit everything in.

The gate valve for the 2nd drain is full open - I only adjust the main siphon. I realize now that I did not need the extra gate valve, but whatcha gonna do

You only need a gate valve on the siphon line, no where else. And the gate valve should be as close to the outlet/sump as you can possibly get it. Otherwise the air in the line below the gate valve can take a long time to purge, it will be noisy, and it might even shake quite a bit as the air tries to rise in the pipe against the falling water.

My latest trick - which works fantastic if you are using 1.5" pipe, is a single-union ball valve from Lowes. 100% plastic (no metal screw) Best part, it's less than $10.

http://www.lowes.com/pd_146171-185-024+LBVUS-112_0__?productId=3130791

This one has a nut on one side that works just like the internal nut on a dual-union $40 valve like you get at BRS. The difference is that the nut both tightens down on the ball, and serves as the means to take apart the device. This valve is completely useless in any other application except maybe hot tubs from what I understand, because you can't shut it off and then disconnect it with water on the other side - the ball slides out when you take it apart. BUT - we don't need it for that! We just need fine control and the ability to lock it down. So you set it up nut-down and submerge the bottom outlet (which sticks out 1/2" or so) and loosen the nut. Start things up, adjust the ball (which spins freely) then tighten the nut when you get it tuned, and it won't budge at all. If you ever need to fine-tune it, loosen it a good amount, make your adjustment, then tighten it down again.

The main siphon line runs straight into the sump. It is submerged about 2 inches. I realize that 1/2" is optimal (just did not pull it yet). Could this be the culprit?

Yes, that is a problem. 1" max under the surface. Any more and the air can't easily purge out of the line

 

[woodnaquanut]

Good morning all!

I cranked up my new system for the first time last night and I need a little help troubleshooting my drains. My problem is that I am getting some "running water" noise from the gate valve on the full siphon line. Everything is glued except the connection into the male adapted that is screwed into the bulkhead.

Everything Floyd said is right on!

One other thing I noticed...
There seems to be some small bubbles being created as water goes over the weir. If these are sucked into the siphon they could be the source of the noise. As the system matures and grows some slime coat the bubbles might go away. Smoothing the weir path would also help.

You should be able to see which drain is getting the bubbles. Might be easier to see w/o the socks. BTW you really only need one sock - on the siphon. It will carry 95% of the flow.

I like Floyd's P trap but you can also use two street ells. If you trim some off the male end of a street ell, it will sit lower in the OF box. That plus a small trim on the slip side of the slip-thread adaptor will lower the siphon if you need to.

And lastly, my pet peeve...
Video doesn't like 'portrait' mode. You just loose lots of visible area. Turn your camera 90 degrees!
End of peeve...