Overflow 1.0 use v 2.0 below
I have been testing and changing this overflow for about 2 weeks now. All together I would say I have about 200 start/stops on the system and it has never failed to start back up.
I am using 3/4" PVC with a 1.5” opening/overflow. After much testing the large opening allows more water to fall into it as it is a larger diameter than just the 3/4" pipe. At least that is my explanation for the increase in flow.
I have also been testing with the length of the outside pipes versus inside and have found that having the outside pipes 1.5” to 2” longer than the inside also adds greatly to the flow output. This length may change for large pipes
I was running my Mag 5 pump (1/2” PVC return line) at just under 2/3 open (ball valve) running the inside and outside at the same at the same length. With increasing the outside length I am now running the pump at maybe 4/5 open. At 100% open the water level rises ever so slowly.
I am pretty happy with how it is performing so far but I have burnt through parts with all of my testing but PVC is cheap so the testing has been worth it.
Output is currently at 2 cups per 1.8 seconds so that is 250 GPH.
Link to larger pics
So I went to setup everything outside this weekend to perform an extended week long test and ran into some issues. Because of these I had to make some design changes. In all honesty about half way of working through these issues I said “screw it” and went into the house to order an overflow box online but turns out not even the new Eshopps nano overflow box (that comes out this month) or the stupid expensive LifeReef nano overflow will fit in my BC29 so then I became determined to get this to work and work correctly.
Overflow would not start back up.
Issue was that my check valve malfunctioned already. DO NOT TRUST OR USE THESE even though I installed a new one you will see a bleeder valve to back it up in the line now.
I also adjusted the height of the inside vs outside tubes to make them even once again. From all my readings this is the best way to make sure you do not break the siphon. Also the outlet to from overflow must be above the bottom on the inside pipe assembly.
During testing if these pipes are not 100% air/water tight you will break the siphon if you have the pump off for an extended period of time simulating a power outage. I actually had to end up gluing (PVC cement) everything for my extended testing. Best way to test for this is to shut the pump off and let the water drain. You will have some slow dripping from the drain pipe for maybe 30 to 60 seconds but after that you should have nothing. If you have a constant drip it means you are leaking air and your siphon will eventually fail causing it not to drain once you start the pump back up.
I am still thinking about picking up an aqua lifter pump for this build in order to always be removing air. At the very least I would turn it on if I leave my house for an extended period of time. I am going to try to pick one up on this Thursday add it to the test to see what it does. I will report back with the results
Terrible gurgling sound.
In my first test setup you can see my outlet gently goes into my sump with no bends (this was silent) but I changed that for the extended testing to mimic how it would be actually installed into the DT. I added a 90 elbow and ran a pipe straight down and the gurgling started and there was no way I was going to run something that sounded like that. After numerous changes I discovered adding any bends over 45 degrees would cause a gurgling sound from the vent tube. My guess is that air is getting trapped in the bend. I was also thinking it could have been the 90 elbows (the elbows have a very sharp bend internally) I was using but after reading more online it seems that this is a common issue with these overflows. After about the 10th design change I decided to add a 3/4” to ½” reducer on the outlet with a 45 elbow (see pics) and run ½” pvc the rest of the way. This allowed me to add the 90 elbows that I would need in order to get it into my sump and it has been silent for the past 18 hrs that it has been running. This also did not decrease my flow as I did not have to adjust the ball valve at all. I still have some very minor tweaks on this to perform so check back on this aspect.
Changed the inlet to include teeth.
Additional protection measures that will be put in place
Will be adding a float switch (location TBD) to turn the pump off in case overflow failure. This would only keep the pump from burning out as my pump inlet height will never allow my DT to overflow if the overflow fails for some reason.
So far so good with the testing. It has been running for about 18 hrs now with two 30 minute “pump offs” and no issues starting back up. The water level in the simulated DT/bucket has not fluctuated at all. I keep on test for air pockets building the top bend but nothing so far.
I will be updating all week as the test progresses
52 hrs strong
Survived some nasty storms today which was a very good test for it. You can see the water was very rough in the bucket.
Edited by jfarabaugh, 08 September 2010 - 08:37 PM.