Hi everyone,

I recently moved into my girlfriends house and have been noticing some issues with the plumbing. Namely the washing machine drain set up (see link below for images). If the washing machine is run on a large cycle the water backs up and pours out onto the floor. I am quite an amateur, but to me it looks like this drain line is not vented correctly. I would like to repair this myself and I am quite handy, but I am not certain how to set up the plumbing properly. I've been using this website (http://www.plumbing-geek.com/washing-machine-pipes.html) as a reference. What I am concerned about is the height of the main drain leading to the sewer drain. I really appreciate any guidance or assistance!

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Thanks,

Mike

venting is not going to help that. in effect, the trap is vented up thru the stack. it is an illegal vent since other fixtures are draining into the stack.
open the drum trap and try snaking the outlet side.

Thanks for the help. I cleaned out the drum and it appears to be functioning again, although there wasn't much in there. This doesn't seem like a long term fix however. Is there any more long term fix or update that I can do or have done that would prevent this from happening in the future?

Thanks again,

Mike

remove what is there... install a larger size pipe, p-trap and proper vent.
when you cleaned the trap, did you clean the discharge side pipe? that is always where debris accumulates.

I would remove that wye at the stack, replace with a 3" tee, run a 3" horizontal branch over to the washing machine , lay a 3" X 1 1/2" combination on it's back with the 1 1/2" vertical for a studor vent, and a 3" x 2" bushing in the end of the combination for a 2" trap and standpipe. That's the only way it would pass code here in NC. It would take a couple hours and less than a Franklin worth of materials and you would never be bothered with it again.

Packy - Yes, I cleaned out the discharge side of the pipe by opening up the drum and snaking it on both side of the drum.

North Carolina Plumber - Thank you for the suggestion. I added to the photo album from the original post a cartoon schematic of your suggestion. Would you mind just confirming that my interpretation is accurate?

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Thanks for your help! I really appreciate this!

-Mike



Edited 1 times.

i'm sure you realize the fitting at the stack can not be a straight tee.. it must be a sanitary tee. same as the fitting you have drawn for the studor vent. so, use a san tee and elevate the studor 6 inches higher than the top of the standpipe and THEN your interpretation will be correct.

A sanitary tee at the stack, and a combination at the studor vent. It looks like you have it figured out. A tee on it's back will work at the studor vent but will not be meet code, or at least in my jurisdiction . Any fittings used below the flood level of the fixture must be drainage fittings and that means a combination, or wye and st. 45.