Herbie / Durso Overflow Decision

[Goodair]

You will have 2, the issue is the .5 drain is too small for your size tank to be a main drain. With a strainer on the main drains, the emergency drains should never be fully used for a long period of time, it will be noisy and easy to know that your main drain is clogged.

 

[HOOPDEEZ]

The emergency drains don’t run as a full siphon, so there is no way .5” would work for that. If the main 1.5” gets clogged it would just flood your house a lil slower. The 1/2” might pull 420gph as a durso, but will pull about double that as a full siphon.

 

[Goodair]

Ok, to clear up confusion, you can use the .5 as the main, if you are on the lower end of the turnover, it would NOT work for a high turnover. Overtime, crap builds up in the pipes and if your valve is fully open, more water will go to your emergency and make noise. You can not open the path any longer to prevent this.

What causes floods is having the return system done improperly. The overflow will only drain as much water as the pumps push. It is 100% dependant on that factor.
Your return chamber holds x amount of water and if water is not entering the sump, the pump will run dry.

When a flood occurs, its due to:
-tank/sump cracking/leaking,
-pumps turning off and sump not being able to hold the water being siphoned back
-Having a huge return chamber and all 4 overflows are clogged.

Tank cracks you got no control expcet setting it up as properly as you can.

Back siphons need proper positioning of the returm nozzles and siphon breaks. They also need proper size sumps to be able to hold the excess water.

How far down are your return holes in the tank?

 

[SoCalVictor]

Just found out that I may not be able to use the 1/2" holes in my overflow after all. The stand I'm using has 2'x4 supports on the back wall of the stand, so it eats into 1.5" from the back. The 1/2" hole would not work because there wouldn't be any clearance for the nut unless I shave the 2x4 in half which might be risky from a support perspective.

It looks like I'll need to go with two 1.5" dursos, one in each overflow. I'll need to glue the 0.5" holes closed with acrylic squares. I could potentially drill 2 more holes on the back wall of the overflow if I really wanted the herbie setup...

The return holes are about 1" down (to the top edge of hole) from the top tank.

 

[Goodair]

Will you be using loc line for your return nozzles?

 

[SoCalVictor]

Yes, likely...

 

[HOOPDEEZ]

Well that solves that. Yes first you have to set the baseline not to flood, but then there is outside factors. For what it’s worth the closest I’ve been to a flood is when my main got totally blocked with algae, and the emergency started to clog with it. The level in the tank started to rise and came close to overflowing. That is what you want to design your system to overcome. You should be fine with dursos but I would not push them anywhere close to their limit.

 

[SoCalVictor]

Once I tune my dursos (using air valve) will it handle more flow than if the other durso gets clogged or once its tuned, the durso's are fixed in flow?

 

[Silent]

Durso is not a siphon so adjusting the valve (air in this case) is just to reduce noise.

 

[SoCalVictor]

Got it. Thanks all for the advice. Will implement this and circle back once all the plumbing is in place.

 

[Gary Inwood]

I had the durso overflow setup on my system, I could never get it set just right so I changed to the herbie overflow and not looked back, its quite and I get better flow.