Vent issue or improper install?

[Hanxious]

I'm working on a house that's been one thing after the next with the plumbing issues. Hoping to catch a break here.

I just installed a toilet and each flush is syphoning the trap water out of the walk in shower. My first thought is a venting issue, and I intend to go up and check it when the weather permits...

But in the meantime, considering how many things have been done incorrectly (by whomever the precious owner hired) I can't help but wonder if the plumbing is to blame.

I've done my fair share of upgrades and replumbs, but never made any major changes, so I'm not sure what looks good, or is improper.

Any help/advice is greatly appreciated.

 

[Hanxious]

The toilet drain runs past the vent and down past the sink and shower lines. The trap pictured is the shower that's being syphoned.

The basement toilet pictured has been flushing fine.

 

[Sponsor]

 

[wwhitney]

The san-tee on its back at the top middle of your first picture is presumably the vent takeoff for the WC.

However, your shower has no vent, which is probably why the problem is occurring. A vent needs to come off at the elevation of the trap, before the trap arm has fallen more than one pipe diameter.

If the pipe running next to the shower trap arm is carrying the lavatory only, and if the lavatory is properly dry vented, then you could use that lavatory drain to wet vent the shower trap arm. You would do that by extending the shower tailpiece just a little to lower the trap to bring the shower trap arm to just below (like 1/4") the horizontal lavatory drain (or alternatively raise the horizontal lavatory drain). Then use a horizontal wye to join the lavatory drain to the shower trap arm, and then the combined drain can proceed to the stack.

Cheers, Wayne

 

[Hanxious]

Thanks so much Wayne. I think I follow you. I'll be cutting into the wall and checking the roof to see if the sink has its own vent.

If it does, I would then be
1. eliminating this pipe (in red)
2. Dropping the trap
3. Y'ing these two (in green)

Does that track?

 

[wwhitney]

You should be able to check that the lavatory is properly vented by removing the lavatory trap arm back to the trap adapter, then peering into the rest of the trap arm. Best case for ease of inspection there's a san-tee at the wall with the trap adapter right in front of it. Worst case the pipe does a horizontal turn and you'd need an inspection camera to see what happens 1' to 5' downstream.

As to the reconfiguration, yes that would work to wet vent the shower if the lavatory is properly dry vented.. Or you could have the shower drain path straight and wye the lavatory drain into it. The elbow just upstream of the san-tee at the stack should be a long turn elbow, I can't tell from your picture if that's what you have. [I can tell the shower drain currently drops into a san-tee on its back; that's wrong, it should be a combo.]

Cheers, Wayne

 

[Hanxious]

The pipe running next to the shower trap arm is carrying the lavatory only, and if the lavatory is properly dry vented, then you could use that lavatory drain, Wayne

Well Wayne, like everything so far with this house, this has to get my anxiety and nerves to 100.

Doesn't seem like the sink is vented.

I went up on the roof to clean the vent. It was a little plugged, but shopvac'd and hosed as far as I could. (it only drops about 5 ft before an elbow.)

Upon further flushing of the toilet, I'm getting gurgling from all three toilet, shower, and sink. Any advice where to go from here?

Like I mentioned, the basement toilet just below this bath is flushing fine (no noise or suction in the bathroom above)

 

[Hanxious]

Oh, and something I forgot to mention, that may or may not matter, this house doesn't have public sewage. There's a septic system.

I was wondering if that could be part of the problem??? I noticed there's an older pipe next to the clean out that I assume was for the sink/shower at one time.

Would running those lines back to that possibly solve my issue or just create more problems?

 

[wwhitney]

This is beyond my direct experience, but I would suggest confirming the vent is unclogged (run water down it, or a camera, or a snake, as necessary). And then dry venting the lav (you can use an AAV if you don't want to open the walls) and using the lav drain to wet vent the shower.

Cheers, Wayne

 

[Tuttles Revenge]

Gurgling of other fixtures when a toilet is flushed generally points to a blocked main drain.

 

[Hanxious]

After I snaked and shopvac'd I ran a hose down the vent and it was draining fine.

This is beyond my direct experience, but I would suggest confirming the vent is unclogged (run water down it, or a camera, or a snake, as necessary). And then dry venting the lav (you can use an AAV if you don't want to open the walls) and using the lav drain to wet vent the shower.

Cheers, Wayne

Thanks for the help Wayne, you have definitely been helpful.

After I snaked and shopvac'd I ran a hose down the vent and it was draining fine.

 

[Hanxious]

Gurgling of other fixtures when a toilet is flushed generally points to a blocked main drain.

That's what I've heard, blockage or venting issue. But the toilet just below this bathroom is flushing fine with no gurgling there or the from the fixtures above. That's why I was thinking maybe a venting issue.

 

[wwhitney]

That's what I've heard, blockage or venting issue. But the toilet just below this bathroom is flushing fine with no gurgling there or the from the fixtures above.

So what about a blockage between where the upper WC, shower, and lav come together at that san-tee and where that combined drain joins the lower WC drain?

BTW, that rubber coupling in the second photo in the OP is the wrong type. Above grade you are required to use a fully shielded version like Fernco Proflex or Mission Bandseal. And it looks like there's a significant transverse offset at that unshielded rubber coupling, a problem the shielded coupling is meant to avoid. Perhaps there's a clog in the transverse offset?

Cheers, Wayne

 

[Hanxious]

So what about a blockage between where the upper WC, shower, and lav come together at that san-tee and where that combined drain joins the lower WC drain?

BTW, that rubber coupling in the second photo in the OP is the wrong type. Above grade you are required to use a fully shielded version like Fernco Proflex or Mission Bandseal. And it looks like there's a significant transverse offset at that unshielded rubber coupling, a problem the shielded coupling is meant to avoid. Perhaps there's a clog in the transverse offset?

Cheers, Wayne

That definitely could be. I didn't like the way that fernco looked, but figured that was just me being anal. Now that you've also pointed that out, I'll look into replacing it with a reinforced as mentioned, snaking for clogs up through there, and try to get them plumbed back up flush when I try the AAV.

I'm assuming that offset came from them pitching the toilet horizontal down, and gluing down to the fernco last.

To avoid an offset, should I start with the fernco transition and work my way up?

 

[wwhitney]

Generally when working between two fixed ends you need to use two (shielded) rubber couplings.

If the plastic riser above the single rubber coupling you have is long enough that the riser could be flexed laterally at least one pipe diameter, then you could get away with one rubber coupling. If that's true, you could try shoving the plastic pipe to the side to line it up properly over the cast iron below and then temporarily strapping the plastic pipe to keep it there, to see if that helps. You might need to loosen and retighten the rubber coupling afterwards.

But the basic answer is that with the rubber coupling absent, the two ends should line up properly without being stressed.

Cheers, Wayne