Herbie plumbing question

[Sethjamto]

I have a dual Herbie setup on my 8ft tank and the drains drop into the sump halfway across the tank. This means that each drain runs horizontally for 4ft and I have no issues with starting the siphon. I have two 1.5" lines that tee into a 2" line and 2" gate valve into the sump. I will more than likely get rid of the 2" gate and go to two 1.5" gates so that I can individually control each overflow. For some reason one is a hair lower than the other and causes a splashing noise with water falling two far over the weir. If I separate them out, I can close that valve a hair more and raise the level of that overflow to where it should be.


....but ......to answer your question, horizontal runs aren't recommended but work great for me at 4ft each. I was warned not to do it, but wanted a cleaner look under the tank and figured I'd try it. If it didn't work, it's just PVC and I could have changed it.

 

[SGT_York]

You cannot run horizontal with a Bean Animal with a herbie it works as all that it takes to start up is to drain the air. In a BA you need enough pressure to lift the water up the first 90. So a horizontal run will severely hinder the startup. For a herbie it works best if you gate valve is after the horizontal run, but not necessarily a problem.

One thing to watch for if you raise the dry emergency ensure that when the siphon is blocked the emergency can handle the additional height without overflowing. I've seen a few people that put their herbie siphon 6" under the overflow then expect the Dry emergency to function with 1/4" of head height which is a flood guarantee. Best method is to start the first run with the siphon blocked to proove that the dry emergency will work without a siphon line at all.

 

[uncleof6]

You cannot run horizontal with a Bean Animal with a herbie it works as all that it takes to start up is to drain the air. In a BA you need enough pressure to lift the water up the first 90. So a horizontal run will severely hinder the startup. For a herbie it works best if you gate valve is after the horizontal run, but not necessarily a problem.

One thing to watch for if you raise the dry emergency ensure that when the siphon is blocked the emergency can handle the additional height without overflowing. I've seen a few people that put their herbie siphon 6" under the overflow then expect the Dry emergency to function with 1/4" of head height which is a flood guarantee. Best method is to start the first run with the siphon blocked to proove that the dry emergency will work without a siphon line at all.

In short, no.

Both systems operate according to the laws of physics. The head pressure required to purge the siphon is identical in both systems (assuming, aside from elbow/no elbow, all else is equal.)

For a drain line using an open pipe, configured identically (size, fittings, topology whatever below that point,) to a drain line with an elbow before the drop off point, the exact same head pressure will be required to purge ALL the air out of the line. It does not matter if the open pipe is 1" below the water level, or 100" below the water level.

Purging the air has absolutely nothing to do with the top end configuration of the standpipe. It has to do with the head height: e.g. the distance from the water level in the overflow to the water level in the sum, and everything with the mess created with the plumbing under the tank affects the amount of head pressure required to start the system. The standpipe configuration is completely irrelevant.

The net effect of the elbow/tee combination (with or without the tee) is the water level can be lower above the elbow (closer to the internal weir/drop off point) than it can be above the end of an open pipe (the weir/drop off point.) E.G. the only thing the elbow does is prevent the stand pipe from sucking air. It has no affect on the head pressure required to start the system, an open end pipe does not negate the advise that dead horizontal runs can and do air lock the siphon, and should be avoided. The position of the valve is completely irrelevant.

The mis-application of physics to justify an assertion, that happens to be inaccurate as well, is not helping anyone sort all of this out. We are not building space vehicles, or sending people to Alpha Centauri, it is not rocket science, but you still cannot beat the physics. The herbie has a use, and it is rather well suited for that purpose. If you don't have room for the BA, run the herbie; the physics don't change.

 

[SGT_York]

Not at all, A herbie is just a straight drop down there is never any time where the water goes up a pipe. That nearly eliminates any start up time. I concur with the purging air comment, but to purge the air in a BA the pipe needs to raise up higher to start the siphon then the overlow water level lowers to the operating level. None of that is required with a herbie open top pipe. The water never raises and lowers, it just raises to it's operating point and goes no higher due to the lack of a true siphon.

Your comment that the elbow before the T only helps to lower the water level is the point that lowing is eliminated with a open herbie so it starts faster. Not sure how this is confusing...

The location of the gate valve is important as the high point in the friction loss will restrict the flow forcing the water to back fill until the head pressure is enough to equal out the flow, which means the horizontal flow fills with water before the head pressure raises sufficiently to move most of the water out. With a BA that means the siphon will not start. In a herbie it works great.

Regardless of what you think you know, the physics work great, rather than think my few tanks are an exception to the laws of fluid dynamics I'm more inclined to believe you do not have a correct grasp of the herbie system.