Pretty much what u are saying is correct. If the valve is fully open then u would have to tune the return pump to the drain. It is unlikely that would happen & if it is draining the overflow with the return pump up all the way then the return pump can't keep up. It wouldn't surprise me if u had to pump 2000 gph for it to keep up with hour setup. Even if u could it would seem like it would be inconsistent.
That is one of the many positives about a beananimal drain. With your existing plumbing u can run anywhere from 200 gph to 2000 gph & the system work correctly. It makes it so much easier to tune the drain to the pump rather then the other way around
They can be even but being u have a exterior box I would place the open channel atleast 1/2" to 1" higher then the syphon. With them the same hieght u can have a issue with the syphon purging it's air. What happens is the open channel takes on water before the water builds up enough to purge the air from the syphon, making it take longer to purge if it does at all. So by placing the open channel higher it eliminates the possibility of that issue.
When I have a interior box & the 90's go straight into the bulkhead in the back of the tank then I drill the holes the same height & the open channel & syphon are even. With a exterior box where the bulkhead is in the bottom I always place the open channel higher then the syphon
What you are calling Emergency Drain #2 is actually the open Channel and it is responsible for determining the height of the water in your overflow box. The concept is that the siphon handles the majority of the flow while a minimal amount flows through the open channel. Siphons are silent, and since the open channel has a very low flow and low turbulence, it will be nearly silent also. The Emergency Drain should be set at your maximum level for tank water. The end of the airline tube from the top of the open channel should be attached just below the level of the Emergency Drain, so that when it is covered, it turns the open channel into a siphon also in the event that the designed siphon should clog. At this point, your overflow should start making noise to alert you to an issue with the drains.Can someone point me to the discussion about the height of the various drains relative to either the bottom or the tank, height of the weir, and/or height of the tank?
Alternately, here's my thoughts:
1. Siphon pipe: the height of the siphon drain doesn't really matter. You tune the water level in the overflow box using a gate valve on the siphon line so the water level in the overflow box is just below the bottom of the teeth of the weir to minimize the height that the water falls, and therefore minimize the noise of the falling water.
2. Emergency drain pipe #1: Set the height of the first emergency drain (elbow down, with the airline, aka a durso) so that the top of the upside down U formed by the elbow pointing down (aka the height at which water begines to flow into this drain) is just below the height of the bottom of the teeth of the weir. This, combined with the water height set by the siphon gate valve, ensures that only a trickle of water flows down this emergency drain. Airline is optional but recommended to create a true Durso that will operate in non-siphon mode.
3. Emergency drain pipe #2 (the open pipe): set this higher than the Emergency drain pipe #1. Ideally higher than the top of the upside down U in Emergency drain pipe #1 (or the height of the air line input to Emergency drain #1 if using an airline) so as to allow Emergency drain pipe #1 to enter full siphon mode before Emergency drain pipe #2 kicks in. ALSO, the height of this open channel should be at least 1/2 to 1 inch below the height of the top of your tank!!! Lower is better. Otherwise you may not get the flow you need in Emergency drain #2 if the siphon and emergency drain #1 both fail.
So ideally there is a relationship between the heights of Emergency drain #1, Emergency drain #2, the height of the teeth in the weir, and the total height of the tank.
I welcome any comments or criticism of the above; we're all trying to design the safest, quietest solution possible.![]()
Sorry, I appear to have confused the terminology. You are correct in that Bean labels the open channel as having the airline tubing. I have added the label of "Durso" in my post above to try to clarify. So my "Durso" is Bean's "open channel". Although I find this confusing as I tend to think of "open" as not having any junk (e.g., Durso) on top of the pipe.What you are calling Emergency Drain #2 is actually the open Channel and it is responsible for determining the height of the water in your overflow box. The concept is that the siphon handles the majority of the flow while a minimal amount flows through the open channel. Siphons are silent, and since the open channel has a very low flow and low turbulence, it will be nearly silent also. The Emergency Drain should be set at your maximum level for tank water. The end of the airline tube from the top of the open channel should be attached just below the level of the Emergency Drain, so that when it is covered, it turns the open channel into a siphon also in the event that the designed siphon should clog. At this point, your overflow should start making noise to alert you to an issue with the drains.
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There are three pipes. The siphon, the open channel, and the Emergency Drain. The open channel has the airline and under normal operation only allows a small amount of water to pass through maintaining the silent function. When the water level rises to cover the end of the airline it turns the open channel into a siphon. Under normal operation, there is no water flowing in the Emergency Drain, a small amount in the open Channel, and the majority in the siphon lineSorry, but I'm confused on the terminology. I'm saying that Emergency drain #1 has the airline tubing. You say that the "open channel" is Emergency drain #2, but then you also say that the open channel has the airline. That seems to be mutually exclusive.