Todays Herbie Question
 

Say you have dual overflows with a primary drain in each over flow. Do you need a gate valve for each primary drain or can you use one gate valve if your drains are tee-ed together?

Not sure, but things might be less frustrutating if you have a gate valve for each overflow since fine tuning the water level on one overflow would affect the water level on the other overflow with just a single gate valve between them.

Agreed...gate valves.

alternatively you can use one overflow as the primary drain and leave the second overflow as the emergency drain. then only put one gate valve on the primary drain and leave the emergency drain open.

I'm not sure that will work with dual overflow boxes..but I may be misunderstanding your suggestion. Using one box as primary and the other box as emergency would make the emergency one run all the time unless the two boxes were at different heights in the tank...which I've never seen done.

Anyway....I can attest that with two overflow boxes, things work perfectly well with two gate valves. Each box has a primary and an emergency. This is exactly what I have running. They do interact with each other...that is...altering one does have an impact on the other.

You could join the two primary drains, and put a single gate valve below the joint. (You would need a single, larger, gate valve) That would probably be the best solution because any adjustment would have an exactly equal effect on both boxes. For that matter, you could also merge the two emergency lines as well. In my case, I chose not to do this for reasons related to feeding twin sumps.

I'm with untamed on this, if your primaries were Tee'd see no reason why a single valve wouldn't work.

My self have thought about converting my 2 overflows quite abit to a Herbie with one overflow being primary and the other overflow chamber being the secondary (single pipe in each). If the overflow weirs the same height would just be filling the second chamber, but would work if raised the height of the weir on the second chamber, thinking less than 1/2".

Thanks,

I'll be working with two overflows with 2ea 2" drains in each overflow into a single sump. The primarys will be tee'd together and the emergencies will be tee'd together. I wasn't sure if I needed a gate valve for each primary before the tee or one single gate valve after the tee.

So going to seeing that big tank soon?

My official comment is No Comment.