drain "tee" silencer questions

[FishyIdea]

I bought a bunch of PVC parts at HD and put together a 2" pvc tee for my 1" drain. Dramatically quieter, but I want to optimize it. So I have these questions based on the diagram below.

A. Should the elbow be submerged, close to the waterline, as high as possible?
B. How much space should be below the bottom half of the tee?
C. How tall should the upper half be? I know too short is disasterous But, is there any gain from making as tall as possible?
D. I drilled 9 3/16" holes in the cap. Enough holes? Too small?

 

[etszoo]

Maybe use 45 s to minimize deflection?

 

[marco67]

A) I'm not sure this matters a whole lot, I usually make mine right about at the water line.
B) You can set it right in the bottom, just back cut it to allow flow. I go about 60deg then make a second cut to take the point off so there is a flat spot that sits on the bottom.
C) The larger Dia. the better here, this section works as a reverse settling chamber or air/ water separator. With 2" I'd say 8-10" (*provided you modify D)
D) I've used this type of venting before and always seem to get "spitting", what works better is a single 3/8" tubing it will allow plenty of air and you can tie wrap it up along the drain line for some extra height. Sometimes these will gurgle for lack of better word, you can add a ball valve and muffler to stop it. A muffler can be just a section of PVC with a cotton ball.

One suggestion on your Tee. The "hard" tee you picture will cause water to try to go up as well as down causing turbulence. Turbulence will make noise and add to the "spitting effect" (*the less spitting the better*).
If it's not too late change to a DWV Tee. The "Drain Waste Vent" Tee is swept down where "A" enters and will help direct flow.

 

[FishyIdea]

Damn, Mark, you know yer stuff!


Plenty of ideas to try, and I do love to tinker!

 

[FishyIdea]

The 2" inch silencer was very good, but not good enough. So, I built a 3" silencer.

A: 1" inch flexible pvc main drain. This kind of tinkering would be much harder with rigid pipe.
B: Standard 1" elbow. IMPORTANT: I lowered the elbow from 2" above waterline to half submerged and it made a substantial reduction in pipe gurgle. A couple of people thought a 45 degree elbow here would be better. I didn't try it yet.
C: A two-inch bit of 1" flex.
D. A 1" to 1 1/2" flush bushing.
E. A 3"x1 1 1/2"x3" tee with a slight downward sweep.
F. An eight-inch piece of 3" pvc. Except for two inch-long "feet," I cut 1/2" from the bottom with my dremel.
G. An eleven-inch piece of 3" pvc.
H. Polyfilter medium not tightly packed and not loosely packed.
I. A 3" pvc cap with a 3/8" hole drilled in the middle.

With the Eheim 1262 full on, there is a little noise in the 3" pipe, a moderate amount of noise up topand a curtain of micro-bubbles that dissapate before they make it into the next compartment.

If I use the ball valve to dial back the Eheim, I can get it down to only a pleasant trickle. I have to test and see how much flow I'm sacrificing for the silence.

 

[FishyIdea]

I switched B from a 90 degree elbow to a pair of 45 degree elbows. Definitely less noise in the "big pipe," but it's still noisey up top. Also, the water level in the overflow went up 1/2".

I think the next thing to try is the airline tube down the standpipe.


Also, eventually, I'll recut the botton 8" pipe to have three little feet instead of two. It's not quite stable enough with two.

 

[FishyIdea]

Holy crap, the airline trick worked like a charm!

The noise is definitely in the pleasant range now. From another room it sounds like rain outside a closed window. Up close it sounds like your neighbor is taking a shower and her drain pipe is in the wall you're sitting next to.

Am I there yet?

Is this about normal or can I get it quieter?

p.s., I knocked my baffle out of place, so after I empty the sump and re-baffle it, I think I'll gain a little more quiet.

p.p.s. This is all with the pump going 100%.

 

[Greg Hiller]

If you decide to go the Durso route all your questions are addressed on this site:

http://www.dursostandpipes.com/