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DanTheMan 12-28-2012 05:11 PM

can i cap my tub overflow pipe?
I am replacing the tub in my bathroom remodel, and the one i bought unknowingly was one without the overflow hole.

After reading this:

It seems it is not necessary, so i bought a drain that pops up and down to close it to just bypass that trip lever. Then i took off the top half of the trip lever housing/overflow pipe and put a pvc cap over it (rational being this long pipe hits the tub where the hole should be and puts the whole assembly at a bad angle for the drain). After talking to my dad he was wondering if air needed to get through the overflow pipe to help it drain. Just confirming that there wont be an issue, i dont foresee one since the pipe will fill up to the level of the tub water anyway when you hit the drain...

nealtw 12-28-2012 06:21 PM

All of that may be true but people do forget that they have water filling the tub. One mistake could be very expensive. Why not just drill the hole? And welcome to the site.

CallMeVilla 12-28-2012 06:49 PM

Your drain must be connected to the ent stack (pipe) to operate properly. My guess is that it is. This will allow proper drainage. If you can be 110% sure you will never let the tub overflow, then you can live without the overflow pipe . . . but it is there for a good reason. ;)

DanTheMan 12-28-2012 07:19 PM

just so we are on the same page the vertical pipe that goes to the overflow there is a junction where the two connect and that is where i capped it with the pvc cap.

I have not drilled out a hole bc i am worried about it not being lined up well and ruining my tub and possibly flaking off the coating on the inside of the tub. If it is possible i could potentially hook up the pipe again. i had some free time today so i did that while i wait on a plumber to install the delta shower valve.

I have all the drywall ripped off around the tub so i can always just pick the tub up again to get in there if i need to.

Wuzzat? 12-28-2012 07:22 PM

One other option is a water level detect circuit that cuts off the water flow with a solenoid valve. The water sensor could be under the tub or on the outside surface of the tub but this is hi-tech, expensive, may be impractical and maybe cost more than repairing water damage.

My tub fills at 6 GPM but I never put this to the test. I guess I should also try it with 2 GPM basins. I'm on city water.

DanTheMan 12-28-2012 07:43 PM

oh you mean vent stack right? yeah there are like three drain pipes i think that go into the vent stack before going out to the septic tank and one is for the tub and toilet in there.

CallMeVilla 12-29-2012 09:06 AM

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It's funny how language can fail . . . The way I hear you, you have capped the overflow pipe inside the wall. (See my modified pic below) This tells me your vent stack is NOT piped above the overflow pipe. One of the key principles in plumbing is "air behind water" which means drainage works best when there is free air feeding into the drain line at or near the source.

Your tub should have a p-trap that connects below the drain pipe. From there the drain will travel a bit but a vent stack (pipe) has to intersect within 36" to guarantee good srainage flow. Since you have the wall open, you should check.

The cap on the overflow should not impede your air flow as long as the vent stack is not above it as part of the overflow piping.

Wuzzat? 12-29-2012 01:01 PM

Your link has taught me something.

When I flush slow-going drains with a garden hose plus adaptors that go from aerator threads to garden hose threads, I never flush the overflow.
Now I find that, out of three basins two have clogged overflows and the remaining overflow cannot keep up with 2 GPM.
All drains can keep up, though.

And I have some evidence that the bathtub overflow is clogged.

Possibly these overflows are there to humor us.

CallMeVilla 12-29-2012 03:01 PM

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Here is another pic of a typical tub, toilet and lav piping arrangement. It can help anyone who is plumbing a bathroom. Notice there is NOT overflow piping because this diagram features a shower floor setup. However, the physics of the drainage is identical for a tub or a shower.

Notice, also the p-trap and THEN the vent stack attachment. That setup would work fine for Dan-the-Man.

DanTheMan 12-29-2012 06:44 PM

Ok so it looks like everything will work out bc you are right shower only systems would not have that overflow pipe. The p trap is right below the sub floor and there is about three feet or so of PVC pipe that dumps into the big pipe running to the septic where other pipes converge and the cent stack goes up at that point. Thanks for that picture.

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