standpipe surges

[fishgate]

Are standpipe surges due to not enough air getting in the standpipe? I drilled a 3/8" hole in my air cap but get surges when there is too much flow. If the flow is low enough, there are no surges. Should I drill another hole and/or enlarge this one?

 

[E30 E T A]

Too much flow from your return pump. You can put a ball valve on your return line or get a weaker pump.

 

[fishgate]

That makes no sense at all. What if you want more flow?

 

[sirreal63]

You have an open channel drain, that means there is only so much room for air and water. As the amount of air decreases, flow increases until there is no more air, then it goes siphon and flushes, at which point air is introduced into the drain and the process starts all over again. If your drain is flushing, you are pushing too much water through it, slow down the flow for the existing drain or if you really want more flow, convert it to a siphon style drain.

I watched your video's in the other thread, you already have way more flow than you really need, but if you want even more convert those drains to Herbie's.

 

[fishgate]

You have an open channel drain, that means there is only so much room for air and water. As the amount of air decreases, flow increases until there is no more air, then it goes siphon and flushes, at which point air is introduced into the drain and the process starts all over again. If your drain is flushing, you are pushing too much water through it, slow down the flow for the existing drain or if you really want more flow, convert it to a siphon style drain.

I watched your video's in the other thread, you already have way more flow than you really need, but if you want even more convert those drains to Herbie's.

OK so that makes sense. You only get so much flow before it goes siphon. That flow I suspect is dependent on how much air can get in behind the water. So I think if I increase the size of my air intake in my Durso standpipe I should be able to get rid of the surges with the flow I want. I'll drill another hole.

 

[sirreal63]

No, adding more air will reduce the amount of water, remember there is only so much space in that line for air and water. To stop the flushing you must slow the flow. You could make the drain line larger but that will involve a lot of work. Reduce the flow or convert to a Herbie.

 

[fishgate]

Are you saying I can have either 250gph or 1000gph but nothing in between? (I estimate that is what I am getting now - the video shows it wide opened it is cut back 75% on each return now) I have slowed the flow (via gate valves) enough to stop the surging but I want more flow then that. It will run mostly without surging and it is not a full surge, just a partial surge. But I'd like to bump up the flow at least to around 350gph.

 

[sirreal63]

The return is a single Eheim 1262, which before head loss is 900 gph going into two drains, IIRC. Are you using valves on the drain or just the return?

 

[fishgate]

The return is a single Eheim 1262, which before head loss is 900 gph going into two drains, IIRC. Are you using valves on the drain or just the return?

I have ball valves on the drains but I am not using them. They are wide open.

 

[sirreal63]

What size is the drain plumbing and the bulkheads on the drain?

 

[fishgate]

Bulkhead drain and all plumbing from the bulkhead down is 1" with all plumbing inside the overflow at 1 1/4 inches as per the Durso instructions.

http://www.dursostandpipes.com/make-your-own-diy?start=3

 

[AFU]

I think you need to drill a smaller hole in the euro cap I always start with a tiny pin hole and move my way up. I agree that it sounds like you are getting to much air there for creating a air pocket then the surge or flush sound occurs. Ill snap a pic of mine and post it up for reference. GL. Seems the drain is always the pia

 

[sirreal63]

If it can handle the full flow of the 1262, which I remember from the video it can, then it should handle any lower flow without flushing. I remember you have a tube in the top of the elbow, how far down in the elbow is it pushed?

 

[sirreal63]

One thing that may be the cause...is any of the drain plumbing horizontal? Horizontal runs can cause flushing.

 

[fishgate]

There is a horizontal run (you can see in the video) but that side doesn't flush, the other side does and that is a straight show down with a minor wiggle.

I have the 3/8" JG tubing shoved in probably an inch or so. I had thought about just putting enough to be tight but didn't. Do you think this could be the problem? I just shoved both in never thinking this would effect flow but perhaps I need to adjust that to be on the very top of the 90.

 

[sirreal63]

Raise the tube up and see if it helps, it can be an issue if it is submerged and not drawing air correctly. I doubt that is it but it can happen.

 

[JP Reef]

If you are getting a flushing action you need to either add more air holes or drill a bigger hole. As soon as you get enough air the water level will stay constant in the overflow and it will be quiet.

 

[channingd]

All you need to do is tune your standpipe flow to the same as your return pump. Dial down your ball valve returning to the sump. That will stop the "burping". If you want to put a bigger pump then you will have to open the ball valves up and tune the flow to that pump flow.

 

[fishgate]

Whelp, I have good news and bad news.

I raised up the JG tubes, which were in the fitting a good inch, all the way to the top of the fitting, and I can go just about full flow now with no surging. In fact, I have to crank back the return flow with the ball valves because it now outflows the Eheim return pump running on full blast. The water coming out is also quite a bit calmer. At full flow it is a lot of water, but not like the boiling over it was doing before.

The bad news is I had to wiggle the JG tube quite a bit to get it out since it is a tight fit and I made the fitting leak just a little. So I went to snug it and it still leaked so I took it out, cleaned off the teflon paste and re-applied it to the fitting. When I put it back in what? huh? yes, that's right, I cracked the GD bulkhead. So now I am down and out until I can get another one from BRS. On well, I have lots of other stuff to do.

 

[sirreal63]

It happens but at least you can get the drains where you want them.