Loud Drains

I thought I understood how they work.

I think I may need more water volume in the DT, because if I get both drains running, the return doesn't keep up unless I close the ball valves quite a bit on the drains.

 

So what I think you are saying is that if you get both drains going, the overflow box does not keep up... so you need more return pump flowing more water.

You need to see which pipe is surging.

Just to see that we are saying the same thing.... you have the main drain... it needs to be throttled to restrict flow. so then the overflow will begin to back up. It will back up and then start draining down the open channel drain. That is really the regulation. The open channel can take a variable amount of water, from a very small amount to a fair amount running down the sides until it makes noise.

If things back up more the open channel will "close"" full with water to the point it creates a siphon and once the siphon is going it will surge and empty the overflow box and break the siphon... and then it will continue to do it again and again.

On initial startup it will surge and make a little noise until it is all purged of air. But then it should settle out and be problem free.

So if the main drain is surging...then you need to throttle it back. Close the valve. Until it stops siphoning/surging.

If the open channel is surging, then the main drain valve is closed too much. It is not draining enough and causing too much water to go down the open channel.

The open channel is the one with the air tube to break the siphon. And of course the middle one is the fail safe if the other two are not enough.