Replace Cast Iron P-Trap or Just Add Cleanout?

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  #1  
Old 10-26-19, 05:11 PM
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Replace Cast Iron P-Trap or Just Add Cleanout?

Hi everyone. Hopefully, this is an interesting post.

The main question: should I just add a cleanout or replace the p-trap?

Other questions: What adapter would I look for to connect the PVC to the iron wye? Any hints on snaking that I'm missing?

I have a slow-draining washing machine drain and I've tried snaking the drain but can't get the snake past (or into) the trap. There's no clean-out closer to the trap, either.

I've torn open the wall and this is what I have:
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I think I want to remove the plumbing marked in red and replace it with something along the lines of the green lines with PVC and a trap that can be dismantled, and leaving an access panel when done. I would leave the wye (marked in yellow) but need some kind of gasket/adapter to connect the PVC to it. An alternative would be to put in a cleanout near the trap but that would be more PVC mixed with cast iron pipe, which seems to not be the best solution.

Any and all opinions/options would be greatly appreciated.
 

Last edited by PJmax; 11-11-19 at 09:32 PM. Reason: imported picture
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  #2  
Old 10-26-19, 06:43 PM
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Actually I've now discovered that I am actually snaking the p-trap. I'm just not getting better flow. The snake is stopping in (or near) the wye, so now I'm at a loss if replacing anything will help with the flow from the washer.
 
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Old 10-27-19, 04:32 AM
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I assume the line you did not mark is just a vent?

If you want better access for snaking you can remove the Fernco (rubber boot) coupling in your photo and snake from there.

I would avoid replacing the trap unless you're just looking for a project. The trap may be attached to the sanitary tee with lead and in the tight space it won't be fun to work on.
 
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Old 10-28-19, 06:06 AM
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Thank you, Pilot Dane for your response. Yes Im also assuming the unmarked pipe is just the vent. Are you talking about the rubber boot around the vent pipe then? Maybe I could put in a clean out wye there? Im otherwise at a loss as to why theres a drainage problem with what Im seeing so I thought maybe the cast iron is that corroded inside. I was able to get a scope down to just before the trap and theres definitely corrosion in the iron pipe. The snake seems to stop at that sanitary tee (And youre right to call it that. My bad calling it a wye).
 
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Old 10-28-19, 10:50 AM
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If you do want to replace the trap, this is how I'd do it.

The black in my drawing is existing, red is new. (Excuse the quick sketch). Basically you're abandoning the old trap and using a new PVC trap into the existing vent.

The other option would be to cut the cast iron trap out leaving as much as you can (basically where your yellow/green/red lines are in the photo) and use a no-hub to connect to the remaining pipe. Cutting and digging out the old lead and oakum isn't a project I'd suggest trying.
 
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Old 10-28-19, 11:10 AM
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If you do decide to re-do the trap. A washing machine drain line must be 2" minimum.

You will see corrosion inside most steel pipe. I've never seen it so bad that it clogged a pipe though. Usually problems are with horizontal runs and the bottom of the pipe rusts through and starts leaking.
 
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Old 10-28-19, 02:18 PM
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I am not that familiar with steel pipe but lower left hand fitting seems awful tight where the fitting comes back up from the concrete to be a P-trap.
I think that is concrete, it is hard to tell.

Are you sure it is a trap and not a TY.

If you decide to go the Zorftd route then I would tap into the straight vertical pipe on the right as you have more pipe/area to play with.
 
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Old 11-03-19, 03:25 PM
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Thank you!

Thank you Zorfdt. I think your idea makes lots of sense. I hadn't thought about just bypassing the entire mess. I've already taken a trip to Home Depot to purchase the parts, but didn't plan for the work properly as Sunday is laundry day and I should have asked my wife to shift days.

Thank you Pilot Dane for the reminder that I need to stay with 2" as I might have forgotten that when buying the trap, esp.

Thank you manden for your response. I hadn't thought about it being a TY but I also don't know why there'd be 2 lines to the sewer so close to each other, either. The trap is, as best I can tell, just hard to clean out. I'll dig around the debris and double check, as well as scope it once I've cut the steel pipe above it.

I plan on reporting back some time in a week when/after I start doing the actual work.
 
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Old 11-11-19, 08:48 PM
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Nope

So it turns out they reduced the 2 fitting and used 1 1/2 pipe everywhere and adapted back to 2 trap and wye, which probably explains the backup problems

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So Im thinking Ill have to dig out the hub at the wye no matter what to get things back up to spec. Im assuming this Fernco donut will do the job at the wye?

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The next challenge, and the reason (I think) that they did it this way is that 2 fittings take up a bunch of space.

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Last edited by PJmax; 11-11-19 at 09:42 PM. Reason: imported/resized pictures
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Old 11-12-19, 11:03 AM
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I’m thinking I’ll have to dig out the hub at the wye no matter what to get things back up to spec.
Unfortunately, yeah. Maybe others will have a better suggestion... but good luck. The old leaded fittings can be a pain to get out.

Depending on where you need some extra space, you can change those 45's out for street 45s. Will save 3/4"-1" in the offset if needed.

Also, that trap is only code-approved if you keep an access panel in the wall. You'll want a cement trap if you're planning on closing up the wall.

Lastly, don't be shy to open up the wall more. You're going to need to open it to the stud on the right to repair, and if you take an extra foot or two off the top, it's not going to make it any harder to finish. The more room you have to work, the better.

Good luck!
 
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Old 11-12-19, 12:57 PM
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Thanks Zorfdt. I'm definitely not afraid to open it up more. In fact, my excuse for opening it at all is that I have a long-term plan of putting a wet-bar in on the other side, so I'll need to have access anyway when I'm ready to add that additional plumbing. The other side is an indoor brick facade, so most of the work needs to be done from this side anyway. I just was avoiding pulling more of that rock wool insulation out for this phase.

As for the trap, I DO plan on keeping an access panel, just because of the problem I'm trying to mitigate in the first place as it seems easier to clear clogs directly at the trap. However, I'm actually not 100% sure how to make this one serviceable, as it seems to be a cement connection on the left, and isn't like an under-sink trap as I would normally expect. Obviously, something has to be a disconnect there and I figured a hubless connection sleeve was going to be my only choice. Is there something I'm missing?
 
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Old 11-13-19, 11:03 AM
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Regarding the P-Trap, you're correct. The disconnect type are usually used under a sink or similar, where there's another disconnect point too. I think you mentioned that's a laundry standpipe - I wouldn't bother with anything disconnecting as you can always easily snake it from the standpipe if needed, though 2" PVC would be rare to clog from laundry.
The no-hub connector is a fine option too, but I can't imagine ever needing to get into it. I would rather use a 2 cleanout on the pipe if needed, so you can snake down it if needed. But either way really works.
 
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Old 11-13-19, 07:53 PM
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I got the lead out

I thought this would be worth sharing, based on all posts I’ve seen saying it’s a real pain to remove the lead from the castiron joint. Well, instead of using a drill bit I used a vibrating multi-tool and cut out a “triangle” and pried the rest of the lead out from there, basically in 1 main piece and 3 small pieces (2 cuts to make the triangle made the small pieces). After the fact, I probably could have done it with one cut and no triangle. Whole process took less than 5 minutes. I made a little photo collage to show the basic process of what I did:


The only reason I didn't go further tonight is that I suspect I will need to suspend the vent stack since they probably relied on the castiron to support it.
 
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Old 11-14-19, 05:26 AM
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I normally use an old wood chisel. The lead is soft enough that the chisel makes quick work of it. Still, not a fun job and you don't want chunks of lead falling down into the drain pipe.
 
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