Durso flushing problem..

[Aragorn]

Scott,

Unless I'm missing something(forgive me if I am), you can keep an good level of water in sump and still have enough room in case of a power outage. The trick is to drill a small hole slightly below the waterline of the return line(s). This way, when the power goes out, the return line creates a siphon and begins draining into the sump. Once the level in the main tank drops below the hole(s), the siphon is broken and no more water flows into the sump. This prevents sump overflow. HTH

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"Remember...Wherever you go...There you are."
Buckaroo Banzai, circa 1978

[CliffJahner]

Okay, I'll take a crack at this. If I'm reading you correct, when you simulate a power outage, it's fine. But when you kick the power back on the pump in the sump is putting the water back into the tank faster than the standpipes can reset and handle the surge, am I getting it so far? Then if I may assume than I'm following it correctly so far, that maybe the 3/4" pipe that is hooked up under the bulkhead is resticting the amount of flow. It stand to reason that when you simulate a power outage, there is no water left in the standpipe. What is left in the standpipe at this point now is just air. Now when you kick power back on water starts to rush into the standpipe, now remember the air in there? The water is going to want to flow down, but the air is going to want flow up, this creates a sort of bottle neck. Until all the air gets to leave there will be resistance and a reduced flow. With a larger pipe you get the same effect but it is not as pronouced as it is with a smaller pipe, the more room the more water it can handle.
So in my reasoning the pipe under the bulkhead should be as large as the bulkhead. But not larger, you might get a waterfall sound because the bulkhead will not be able to keep up with the flow. Now the standpipe above the bulkhead should be larger than the bulkhead. Think of it as a reserve, it lines up the next water that is to be transported out. The reason it is larger is so that it will have no problem in keeping up with the demands of the bulkhead. And remember to keep everything above the bulkhead the same size(ie. 1 1/4" standpipe = 1 1/4" elbow). I surley hope this helps so you can stop tweeking it and just enjoy it!

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Cliff Jahner

"Simplify, Simplify."- H.D.T.

[ScottWV1]

Aragorn, the problem is not with the draining of the tank following a power-down scenario, it's when the power comes back on and the tank begins to fill up.

Cliff - you are exactly correct in how you state the problem. One thing that you seem to have wrong is that my bulkhead is not in the bottom of the tank, but rather at the top of the tank in the back glass, just below the tank framing. So, my bulkhead is at the top of the standpipe. The elbow at the top of the durso design screws directly into the bulkhead, then the bulkhead goes directly into a tee and the drain line from the tee goes directly down to the sump.

I follow your thoughts on the air getting trapped in the drain line, but I'm not sure I follow your thoughts on increasing the size of the flex tubing that runs from the bottom of the standpipe tee to the sump.

In the original durso design, the standpipe is above the bulkhead and richard makes it very clear that the standpipe must be larger than the bulkhead. So, in my design, I have simulated a bulkhead at the bottom of the standpipe by reducing the pipe sizing at the bottom of the 1" standpipe to 3/4" flex tubing.

I have spent so much time and energy working on this standpipe portion of my setup when it was supposed to be a no-brainer!!! It has been suggested (Ceorl) that a reduction from 1" in the drain line is not necessary and only restricts the throughput of the overflow/drain. With so much time already wasted, I simply decided to imitate the original design as much as possible!!!! When I accomplished that, the design magically began working as everyone has been telling me it would.

BUT - now I have this problem (which I have NEVER heard anyone else complain about) where when I first power up the return pump, the tank fills faster than the return line primes itself and stabilizes....

If it is because of the air caught in the drain line, then why doesn't everyone else using the durso design have this same problem? I guess this could be tested by ensuring that the end of the drain line (at the sump end) is not submersed in water. Then, upon power up the water trying to drain from the tank would not have a hard time pushing the air out of the bottom of the drain line - obviously this would cause some redesign issues for how my drain lines feed into the sump, but I guess I can take all this one step at a time...

Any other thoughts?

[CliffJahner]

Sorry I've been trying to help on a different design[img]/ubb/frown.gif[/img]. About the only thing I can suggest is maybe reducing it further down the line. If I read you correctly it is reduced 8" down from the top into a 3/4" flex hose, and then the water travels another 5' to the sump. Is it possible to reduce it further down say about 2' or so. Doing this might allow it to handle more water until it can catch up with the pumps. HTH

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Cliff Jahner

"Simplify, Simplify."- H.D.T.

[Aragorn]

I'm stumped! Fresh outta ideas! Sorry Scott, I tried buddy.

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"Remember...Wherever you go...There you are."
Buckaroo Banzai, circa 1978

[ScottWV1]

Well, I extended the standpipe almost 2' more - that's makes it around 30" (from the tank bulkhead to the point in the drain line where it is reduced to 3/4" flex tubing). It seemed to prime a little faster, and I had to give it a tad more air to get the water level in the overflow where I wanted it.

Problem is it still wants to overflow the tank before it primes. As I stated in a previous post, even if the overflow line is NOT submersed under the water level in the sump, it still doesn't help it prime faster...

I could extend the standpipe another 1" easily, but I'm not seeing that as a solution since the added 2' didn't make a significant difference.

I could expand the standpipe for the length between the bulkhead fitting and the 3/4" tubing to maybe 1 1/2", but once again I'm missing the "scientific reason" for the slow repriming and until I get it, it's difficult for me to try to solve this hap-hazardly.

Got opinions??