How to Drain/Vent a Washing Machine

[J. Lovell]

Happy 4th everyone! I'm new to this site, so please be gentle. I'm a 5-or-so-year diyer that mostly figures things out on the internet and I need some advice on how to drain a new laundry room area that I'm installing in the 2nd floor of an enclosed stairwell for the upstairs tenant of my 2-family house. There is currently no plumbing nearby, so I need to run it down a floor and then over to the basement. I've prepared a sketch showing a rough plan - the washer will pump into a 2" riser flowing down to a P-trap and then over to a 2" vented (1.5" vent) drain that will fall 12 or so feet to 90 and into the basement with 3 or 4 more bends to get it to the main stack. I read that I need a 4 or 5" min trap arm before the big drop and I think I just read that I need 30" min from the bottom of my trap arm to the top of my riser. Does this seem reasonable?

I also want to install a drain pan under the washer and condensation dryer that I'll pipe using 3/4" to the 2" drain... and I think I'm just now realizing that this will mean my p-trap needs to be below the floor in the joist area. Any help is much appreciated! Thanks everyone.

 

[WorthFlorida]

May be able to use a condensate pump. Just take the discharge tube to the washer riser.

https://www.homedepot.com/p/Little-...nn151UuGwhmARMAS6YsaAgWFEALw_wcB&gclsrc=aw.ds

 

[Sponsor]

 

[J. Lovell]

May be able to use a condensate pump. Just take the discharge tube to the washer raiser.

https://www.homedepot.com/p/Little-...nn151UuGwhmARMAS6YsaAgWFEALw_wcB&gclsrc=aw.ds

Thanks for the tip! I hadn't thought of one of these. For better or for worse I generally try to find the most basic solutions, in an effort to minimize future failures... That being said sometimes that just means that I put in a bunch of extra work in the beginning and eventually fall back to the condensate pump solution. In this case I ended up going with a 4" oatey floor drain with 2" pvc drain pipe. I'll see if I can post an update with some photos.

 

[J. Lovell]

OK, so I tried to add some labels to my photos, but I imagine most of the folks here will know what they're looking at anyway. I bought a code summary book called Code Check that was pretty useful on things like pipe size, min/max trap height, min/max trap arm length and min/max riser height above trap, etc.

One thing I didn't label in the photos is the air admittance valve I added on the vent line so I wouldn't have to pipe the vent up through the roof. I wasn't able to find great info on that, so hopefully it'll be good enough. If anyone has any comments whether good or bad I'd love to hear them before I try to install the washer/dryer next weekend. Thanks!

 

[J. Lovell]

It looks like my downstairs photo didn't get uploaded. I'll try again.

 

[Jeff H Young]

We run 1 inch pvc right out the side of the house. but we have no cold weather. Installation looks good!

 

[Reach4]

Looks good, except that you probably want to add a strap/support to the standpipe for mechanical strength.

The little cleanout at the bottom of the standpipe trap is not useful but you can leave it no problem.

Drier vent short and through outside wall is good if practical. The outside dryer vent should have multiple louvers rather than one big flap. That excludes birds.

 

[WorthFlorida]

I've never heard of a condensate dryer before. Can the floor drain be use for the condensate? I really do not know how much water comes out during a typical drying cycle.

The only problem I see is if the floor drain is only there for an accidental overflow, the trap will dry out. Either it's used or a trap primer keeps it full. The floor drain is slightly different and two ways to get water to it.

Just google " trap primer". One method, and you see this most times in public restrooms that will have a floor drains, is from a sink drain. Before the sink trap a pipe takes a little water at the drain extension to a fitting on the floor drain. Another is a trap primer on the cold water line that drips at a controlled amount of water to the floor drain.

Keeping the trap full by dumping some water down it gets tiring after a while.

 

[Reach4]

I've never heard of a condensate dryer before.

They are normally called "ventless dryers". https://images.homedepot-static.com/catalog/pdfImages/55/552c2167-a7ea-4193-b66c-a8efee4c71d0.pdf would be an example.