[sphelps]

Originally Posted by fishytime

I see one problem with your drawing Sphelps(other than its far more complicated than it needs to be)....with the two drains merging into one, the only way to tell if something has clogged the primary drain is if you visually inspect it....if you run each individually, the primary is plumbed down below the water line of the sump(making it silent) and the emergency is plumbed just above the water line so you can hear it trickle if something has clogged the primary.

Like I said you have options and there are many ways to do these types of overflows. However everything in there serves a purpose, for example:

The siphon tube takes water from the base of the overflow preventing too much build up which is common with overflow boxes and the hole breaks the siphon during a power cut or shut off which prevents the entire overflow box from draining.

The standpipe skims the surface water preventing surface scum from being trapped in the box. The standpipe also allows more tolerance, so if your flow changes slightly over time it won't effect the noise level. This is a really nice feature, less tinkering is always good especially if you're away for a while and have someone watching the tank. The last thing you want is to explain to someone how to adjust your drain to match your flow and you won't get the panic phone call becuase the tank is making crazy noises. The standpipe also allows you to use a ball valve instead of a gate valve which are easier to find and significantly cheaper.

The reduction in pipe size in the return also serves a very important role, it prevents a pressure drop which can in some cases cause oxygen to liberate from the water creating micro bubbles.

Other than that I don't see the complication, but we all see things differently and we should do things that make sense to us within reason. If one chooses to omit certain parts or do things completely different that's there choice. My intent was only to show an example of another alternative, like I said the drawing was made for someone else but works well as a visual add for other people. I personally wouldn't recommend a Herbie to someone just starting out becuase it is a more complicated system which is why I never mentioned it in the first place.

Also about the tee in the drain I already mentioned to omit that:

Originally Posted by sphelps

I would suggest you don't tee the two drains together at the sump as shown though, keep them separate for best results. You can also use a stock-man style standpipe rather than an HGB.

The reasoning however isn't related to what you said but rather to noise, if tee'd them together the noise from the primary will echo up the secondary creating a gurgling noise which will be hard to eliminate. I realized this after I made the drawing and didn't feel it was necessary to change it as I always note to omit that part when I post it.
If you did tee the lines together you would certainly be able to tell if the primary was clogged as you would clearly see more flow going though the standpipe which will also make a little more noise but at least it wouldn't sound like a toilet exploding