Bathtub rebuild drain issues!!

[deprived]

Okay. I messed up - I admit that.

I tore out the old shower in our 2008 Tiffin and replaced it with a bathtub. It was a huge effort that took several weeks to complete.

And now for the bad news.

The new tub fills up with drain water from the bathroom sink because the new tub sits about three inches lower than the old shower. That little bit of difference is just enough to allow the sink to drain partially into the tub which fills up with about one or two inches of water.

I have two choices to fix this, as far as I can see.

1: rip out the new tub and rebuild the entire thing. Let’s call that plan “B”. Or plan “Z”. I really, really don't want to do that.

2: make the tub drain pipe a bit lower and plumb a new second line to the grey tank. This new line from the tun drain will drop down a few inches beneath the floor and enter the grey tank from the side rather than the top. This will diminish my grey tank capacity a bit but it’s still a hell of a lot easier and cheaper than undoing a month’s worth of work.



There are some issues with cutting a new fitting into the grey tank but I’ve see a few methods using ABS fittings and solvent-cements that seem to work well. That part is tricky but surmountable. Otherwise it is a fairly straightforward job.


I’m not saying this is a perfect plan (or even a good one) but I wanted to put it out there to see what you all might have to say in terms of other ideas or improvements to the plan.

I found a picture of the old drain, and I can see that it sits about three inches higher than my new configuration.


NOTE: my diagrams are not all that accurate but I think they illustrate my situation.

[deprived]

The fix wasn't all that hard, really.

Ended up running the new line to the top of the grey tank and affixing it with marine epoxy. The tub drains great now!

[Housted]

I used one of the hepvo to eliminate the drop of the trap in the basement from the tub to get more clearance. Works great.

Housted

[VAHillbilly]

Have you considered a HepVo valve? Casita uses this in their showers to prevent gray water flowing into the shower. This is a link to their website http://hepvo.com/hepvo-waterless-valve/

I have used the HepVo valve without issue.

[time2roll]

May as well put in a pump and check valve 😉

[DutchmenSport]

Easy solution! Why didn't anything think of this! Just remove the bathroom sink! Problem solved! :B

[MrWizard]

I'm no plumber
But I think he will have problems until the bottom of his tub, his above the level of the drain pipe
He can replumb everything or anything
But if the bottom of the tub, aka tub drain is below the drain pipe on the floor there Wii always be water in his tub
It will not drain completely, when used

He's has to change the relative positions,
Either raise the tub
Or install new lower drain for the tub

[magicbus]

If the "fix" is to have the tub drain into the waste tank at a lower point, why not leave the tub where it is, put in the lower point waste entry point, and then plumb the sink into the tub drain using the new lower waste tank entry. Then you just need to cap the old sink drain entry into the top of the tank.

You will lose a couple of gallons of gray water storage but you don't have to raise the tub you just installed.

Dave

[Lantley]

I assume you cannot access the plumbing without removing the tub? If you can squeeze in a check valve somewhere my thought is the tub needs to come out.
Creating a new connection at the tank is a step in the wrong direction.

[MrWizard]

So replace the straight tee, he installed
With the curved sanitary tee ?

eHoefler wrote:
Where the drain line enters the tank, install a sani tary tee vertically at the tank, have the sink plumbed to go in the top of the tee andd the tub into the side.


https://www.nachi.org/gallery/?level=picture&id=2650

[time2roll]

The fix looks like you are dropping the tub drain line below the floor level shown in the picture. I like the solution if you can make access to that area. As long as the tub is higher or level with the top of the tank I think it will work fine with no need to raise the tub.

[4x4van]

Am I correct in assuming (from your diagrams) that the bottom of the tub is now lower than the drain pipe (that is running along the floor)? If so, then the tub will never drain correctly, even without the sink being in the picture.

If it were me, I would redo it right and raise the tub so that the bottom of the tub is above the level of the drain pipe. Class C's typically don't have an overabundance of grey/black capacity anyway, so doing anything that would reduce that would be a no-go in my book. But if that's OK for you and your use (full hookups rather than boondocking?), then your idea of a separate drain into the side of the grey tank would work, IF you can be sure of getting a good seal at the new entrance into the grey tank.

[wolfe10]

I would look into either a ball valve for the shower drain (closed except when showering) or a check valve/one way valve for it.

A plumbing supply house would be my first stop for ideas.

[SWFL_FlyFisher]

Other than the sink draining into the tub, are there any other issues (does the tub drain if the sink is not in use)? If it empties properly with your new setup and the only problem is sink water draining into the tub, why couldn't you give each a dedicated drain line into the grey tank as in your "fix" above, but rather than plumb into the side have the new line go into the top like the original?

[eHoefler]

Where the drain line enters the tank, install a sani tary tee vertically at the tank, have the sink plumbed to go in the top of the tee andd the tub into the side.


https://www.nachi.org/gallery/?level=picture&id=2650