How to stop Sump Drain Gurgle?

[fkshiu]

If you've got an overflow with 2 bottom drains (e.g. AGA Megaflow), there's the "Herbie" method from RC. It's essentially 2 vertical standpipes in the overflow, one taller than the other. The shorter standpipe flows down into the sump through a gate valve which is adjusted so that the overflow water level is at a height between the shorter and taller standpipes. Don't have the link with me now, but by all accounts it's dead silent.

If that's not possible, I've seen people put a Stockman standpipe on the final downward elbow before the water hits the sump.

The gurgling/splashing is caused by the air that's introduced from the overflow. A Durso, while silencing the overflow, can actually make the gurgling at the sump worse because of the additional air it introduces up top.

The Herbie method is silent because there is no air introduced in the first place. Water merely falls down by gravity. The Stockman just before the sump method works because the air added up top gets flushed out by the Stockman just prior to hitting the sump.

[Matt]

I've taken a slightly low-tech approach, which was to cut a 2l pop bottle so that the down-flow was just barely underwater, and it overflows back up and over the side. I cut one side a little lower to allow the water to exit smoothly, and it got very quiet. I can make it almost silent, but I have to let the water make some noise, though, or I get frustrated by the sounds of fans and pumps, and I like water noise better than machine noise. As an added bonus, it brings all the bubbles back to the surface before they enter the sump.

[GMGQ]

I use the herbie method. It works Beautifully.

I use it in my overflow box.



So on that drain where the rolled up gutterguard is, at the bottom, there is a gate valve that chokes back the flow until there is no gurgling. The gurgling is from the drain sucking down air. Once it's choked back, it's more like a syphon with no air sucked down. Therefore, no noise!

Originally Posted by fkshiu

If you've got an overflow with 2 bottom drains (e.g. AGA Megaflow), there's the "Herbie" method from RC. It's essentially 2 vertical standpipes in the overflow, one taller than the other. The shorter standpipe flows down into the sump through a gate valve which is adjusted so that the overflow water level is at a height between the shorter and taller standpipes. Don't have the link with me now, but by all accounts it's dead silent.

[fkshiu]

Sorry to hijack this thread but GMGQ, is that is U-tube HOB overflow? If so, which brand or is it a custom job with the dual drains?