External box of overflow and bulkhead size

[SallyWho]

I forgot to ask if I could downsize the bulkheads on the exterior box of my Modular Marine overflow. The bottom three bulkheads are 2", which is a bit bigger than I need. Reducing it down on the PVC leading to the sump is no problem, but there's no room inside the box to reduce it. There also isn't much room for two u-bends with 2" pvc. Instead of trying to do a u-bend for the primary siphon, can I just use a flat strainer? Then I can do a u-bend for the secondary siphon (with the siphon break hole drilled in the top), and a straight pipe for the emergency drain. As a matter of fact, can I use a conical strainer on the 2° siphon? Just measure the pipe to be shorter than the emergency drain pipe, and stick the strainer on top? Or do I need the u-bend with the siphon break in order to dial it in for silent and safe operation? Conical strainers on both drains, just adjusted to different heights? I'd appreciate any input from anyone else running bean animal overflows with cramped exterior boxes!

 

[Redleg]

I'm not running bean but I've got quite a bit of plumbing experience. I would try and get some reducer bushings. My local Lowes has them in 2"x 1" and 2"x 3/4" in stock. you may be able to find them in 1 1/2" and 1 1/4" also. Any of those options might give you the space to build your bean animal the traditional way. I'm running my Herbie setup with a conical strainer inserted directly into a bulkhead to save space in my smallish overflow box.

 

[SallyWho]

I'm not running bean but I've got quite a bit of plumbing experience. I would try and get some reducer bushings. My local Lowes has them in 2"x 1" and 2"x 3/4" in stock. you may be able to find them in 1 1/2" and 1 1/4" also. Any of those options might give you the space to build your bean animal the traditional way. I'm running my Herbie setup with a conical strainer inserted directly into a bulkhead to save space in my smallish overflow box.

Thanks! I'll go pick some up and see if they can reduce the 2" pvc to something more reasonable without cramming my exterior box.

 

[ca1ore]

You sure they're 2"? I've got what I believe to be the highest volume MM unit and the three drain bulkheads in the external box are 1 1/2". Depending on your flow goals, you may be able to downsize the drains. I'm running about 1,600 through my 36" overflow. I kept the secondary and emergency at 1 1/2", but did downsize the primary to 1" (I have a long drop). My suggestion would be to not put a bushing into the bulkhead, rather put it into a union; that way should you want to go back to the native pipe it is easy to do so.

Using a flat screen instead of a U bend on the primary is fine, I do the same.

 

[cracker]

I'm not using the utube on my full siphon. It is pretty short. Works fine for me.

 

[SallyWho]

You sure they're 2"? I've got what I believe to be the highest volume MM unit and the three drain bulkheads in the external box are 1 1/2". Depending on your flow goals, you may be able to downsize the drains. I'm running about 1,600 through my 36" overflow. I kept the secondary and emergency at 1 1/2", but did downsize the primary to 1" (I have a long drop). My suggestion would be to not put a bushing into the bulkhead, rather put it into a union; that way should you want to go back to the native pipe it is easy to do so.

Using a flat screen instead of a U bend on the primary is fine, I do the same.

Ope, you're right! I misread the specs (I've got the 1800gph MM). The drain bulkheads are 1.5". The same applies, though: two u-bends in the exterior box would be cramped as hell. But if using a flat strainer for the 1° is acceptable, that gives me a lot more wiggle room! As the drain pipes exit the box, I've got them reduced them to 1.25" (because that's the size of PVC that would fit in my car...). My returns are 1" (because that's the size glass hole saw I had...). I need to do a little more work on the stand, and then I can dry fit all the plumbing! Thanks for the input, ca1ore!

 

[SallyWho]

I'm not using the utube on my full siphon. It is pretty short. Works fine for me.

Just a straight vertical pipe?

 

[samnaz]

@Water Dog has the solution for this...

 

[SallyWho]

@Water Dog has the solution for this...

@Water Dog is one smart cookie. I think I'll use this exact design!

 

[SallyWho]

As a follow-up question: do I have to glue these in, or can I just friction fit the pieces inside the box? Same with the lock line returns- glue or just shove together really hard?

 

[cracker]

Just a straight vertical pipe?

Yes. I also like the setup from waterdog . also never really got the why's of the utubes & found they weren't necessary at least for me .

 

[Water Dog]

As a follow-up question: do I have to glue these in, or can I just friction fit the pieces inside the box? Same with the lock line returns- glue or just shove together really hard?

Friction fit the pipes in the external box. It allows for the ease of pipe height adjustment and cleaning.

 

[ca1ore]

Yes. I also like the setup from waterdog . also never really got the why's of the utubes & found they weren't necessary at least for me .

The purpose of the U tube is to prevent a vortex forming and sucking air. As long as the opening of the drain is far enough below the equilibrium water level in the box it won't happen; but if closer it can and the U prevents it. So depending on the situation a U may not be necessary. To some extent it's also a holdover from the durso days where the U helped to muffles the drain noises. If asked, my suggestion is to use a screen (either flat or standard) on the primary, a U with vent hole on the secondary and a regular stand pipe (upsized if possible) on the emergency.

 

[cracker]

Thanks Calore , I could try it with nothing to lose .
I could see this when trying to push more & more water is pushed thru the box.

 

[SallyWho]

Okay, I'm still working on this. I know, it's taking me forever. Here's my current conundrum. I accidentally ordered a flat strainer that was threaded, instead of slip. If I use a threaded/slip adapter so it fits snugly in the bulkhead, it's too tall to allow a 1.5" PVC u-bend for the secondary drain (and there's still not enough room to reduce that 1.5"). But without the adapter, it just kind of...sits loosely in the bulkhead, which I'm guessing won't work (will it?). So, loosey-goosey strainer sitting in bulkhead, so I can have a u-bend; OR strainer on adaptor with the secondary drain just being an upright pipe like the e-drain? Thoughts?

 

[Will Milberger]

I have a small conical on my primary and two straight on the others. Works fine