Herbie overflow

[Chbix]

Dual over flow tank, each over flow has a 3/4 full siphon drain with a strainer and gate valve, also a 1" open emergency drain. Do the lengths of the drains need to be the same relative to each overflow? Ie the 3/4" tubes need to be the same along with the 1" tubes each being the same length? There is approximately 10" different from the 3/4" drain to the 1" emergency drain, but given trying to push them down into the bulk heads I am not sure they are equal from one overflow to the other.

 

[P-Dub]

If I understand what you are asking, I don't think it matters. Which is longer by 10 inches the 1" or the 3/4"?

 

[Chbix]

The 1" emergency drain is approximately 10" i guess taller is the correct term than the 3/4" full siphon.

 

[Chbix]

Im not sure if I explained it right, refer to the picture. Red line is 3/4 full siphon, blue line is 1" emergency drain. There is about 10" between the red line and blue line in each over flow. My question is does the red line in both over flows need to be the same height and same with the blue line?

I ask because I am getting much more flow from the left drain to the other, I know some of this has to do with the fact the left drain is pretty much a straight shot down to the sump and the right drain has 2 90's and about a 3' run to the sump but just having a hard time dialing this in. I think I need more water in the sump as well.

 

[Snoopy 67]

According to GMAC Reef the difference should be 6 inches.
Easy fix to make them equal with a slip connection & pipe.
No need to glue them. IF you have ball valves on the main drains change them out for GATE valves.

 

[Chbix]

According to GMAC Reef the difference should be 6 inches.
Easy fix to make them equal with a slip connection & pipe.
No need to glue them. IF you have ball valves on the main drains change them out for GATE valves.

I followed the attach diagram which said 6" or more. Is there a reason to not go more?

I did not glue and they are schedule 80 gate valves

 

[Snoopy 67]

Waterfall noises in the overflow box is 1 reason to keep it higher.

 

[Chbix]

Waterfall noises in the overflow box is 1 reason to keep it higher.

The emergency drains are like maybe 1/4-1/2" below the wier teeth. All the noise is in the sump currently as I dial this in.

 

[DCR]

The imbalance in the flow between the boxes is due to small differences the inlet weir heights relative to the tank water level. It should not matter about the relative elevations of the stand pipes and changing them is not going to help balance the boxes. That is the problem with dual overflows. It is difficult to get the tank and overflow weirs perfectly level so the flows into each box are balanced. I think your standpipe elevations are fine

To keep the waterfall of a Herbie quiet, you should have a small amount of water going over the overflow all the time. If there is noise coming from the sump, it is likely from a combination of low flow through one of the siphons and the gate/ball valve located too high above the water level in the sump. This creates a negative pressure downstream of the valve that causes dissolved air to degas and get trapped around the valve creating noise. There is not enough fluid velocity to keep it flushed out. It is not operating as a liquid full siphon. You either need to increase the flow or locate the valve down near the water level of the sump.

 

[Chbix]

The imbalance in the flow between the boxes is due to small differences the inlet weir heights relative to the tank water level. It should not matter about the relative elevations of the stand pipes and changing them is not going to help balance the boxes. That is the problem with dual overflows. It is difficult to get the tank and overflow weirs perfectly level so the flows into each box are balanced. I think your standpipe elevations are fine

To keep the waterfall of a Herbie quiet, you should have a small amount of water going over the overflow all the time. If there is noise coming from the sump, it is likely from a combination of low flow through one of the siphons and the gate/ball valve located too high above the water level in the sump. This creates a negative pressure downstream of the valve that causes dissolved air to degas and get trapped around the valve creating noise. There is not enough fluid velocity to keep it flushed out. It is not operating as a liquid full siphon. You either need to increase the flow or locate the valve down near the water level of the sump.

Thank you for this. Both valves are just below the bulk heads (after a union on each one.) for some reason I missed this point during my research in the herbie system. It took some time and a lot of adjustments but i believe I have it dialed in. it takes about 3-4 minutes after I turn off and restart the pump for it to go quiet but I can live with that. I did realize that I have my emergency drains about 4" above the water line in the sump and the trickle causes more noise than anything else but big picture thats an easy fix once I decide if i want to add some elbows off or just rotate the unions. Thanks for the help.

 

[DCR]

If the emergency drains (which are really just the normal overflows) are above the sump water line, that will create some noise. That is probably the main contributor. I think it is acceptable to submerge them slightly below the water line 1-2".

I also normally like to use a U-bend or two elbows on top of the overflow and drill a small 1/8" anti-siphon hole in the top of the U-bend. This Durso type standpipe will keep the overflow quiet. If you have a true emergency (dry pipe) like a Bean Animal, then it can be open top. You have to be a careful about the elevation of the U-bend. You want the top of the U-bend below your maximum tank level so that it can turn into a full siphon if necessary, but not so low that it creates a water fall of more than 1/2" during normal operation. I normally just press fit it so I can adjust it rather than gluing. If you ever submerge the U-bend anti-siphon hole, it turns into a full siphon and really carries a lot of water flow.

 

[Snoopy 67]

There is supposed to be some noise from the emergency drains to alert you something is not right.

 

[Chbix]

There is supposed to be some noise from the emergency drains to alert you something is not right.

Yes currently it will drip and catch my attention. Was able to get it dialed in pretty good at %50 on the pump, so it in theory should be pushing 1000-1300GPH (on the low end of that considering the pump is rated for over 2600GPH, 50% of that minus the fittings and about a 30" head height. I like that idea though that its silent enough that emergency flow is catching my attention.

 

[Snoopy 67]

As long as you are happy.
Let it run for a while then you can see if you want to up the pump & reset for more flow.

 

[Chbix]

ive read a lot of conflicting info on sump turnover. Some people are saying 10x tank volume for sump flow, others are saying 3-4x.

 

[LadyTang2]

ive read a lot of conflicting info on sump turnover. Some people are saying 10x tank volume for sump flow, others are saying 3-4x.

4x

 

[Chbix]

4x

I think im right at 4-5X, and thats just where the plumbing is happy and quiet. The return pump is rated to 2600GPH and is running at dead on 50%, so 1300GPH, with the plumbing and head height im estimating its probably more like 1000gph flow split into 4 returns, and at a 180g tank would be just about 5x flow.