Hi All,

I'm a new home owner (or should I say owner of a really old pre-owned house). I'm looking to add a washing machine on the second floor in my pantry. I installed the dryer vent, the electrical, and have the rough plumbing pipes running down into the basement ( only the hot/cold water is connected so far, not the drain pipe.)
Also since I am on the second floor I bought one of those washing machine pans to place under the washer in case of a leak. I want to plumb this into the drain pipe so if there is a leak it flow into the drain and not just overflow onto the floor.

My drain pipe/standing pipe is 2" pvc, the connection to the washing machine pan is a very short 1" stub that came with it.

Bear in mind that space is tight, here are my questions:

1) Is there a minimum distance that the p-trap needs to be off the floor? There is not a cleanout on the p-trap. It will make is a lot easier if I can put it as low as the floor so I don't have to build a huge platform to sit the washer on.

2) What is the minimum distance that a waste tee must be above the top of a p-trap to ensure that water will flow through the trap and NOT up through the tee into my washing machine pan?

3) I do not have access to a proper vent stack or wet vent so I was thinking of using an Air Admittance Valve above the drain pipe, after the p-trap. Any problems with this?

I have attaching a photo of a rough dry fitted setup, please excuse the duct tape.

I'm really grateful for any help, and since this is my first post please let me know if it is too long or too wordy.

--Bruce


Edit:

I just read another related post and a different option would be for me to put the trap in the basement, I just assumed that would be way to far of a drop. Can I just do this and then add the proper venting close to the p-trap?

1) Is there a minimum distance that the p-trap needs to be off the floor? There is not a cleanout on the p-trap. It will make is a lot easier if I can put it as low as the floor so I don't have to build a huge platform to sit the washer on.

The trap wants to be as close to the floor as possible.

2) What is the minimum distance that a waste tee must be above the top of a p-trap to ensure that water will flow through the trap and NOT up through the tee into my washing machine pan?

In order to insure the washer discharge won't back up into washer the waste tee for the pan would have to so high it wouldn't drain the pan.

3) I do not have access to a proper vent stack or wet vent so I was thinking of using an Air Admittance Valve above the drain pipe, after the p-trap. Any problems with this?
No problem but I would install the AAV on a raiser as tall as the stand pipe.

4)I just read another related post and a different option would be for me to put the trap in the basement, I just assumed that would be way to far of a drop. Can I just do this and then add the proper venting close to the p-trap?

If you could lower the trap a few feet you could install the pan drain tee in the stand pipe with no worries. I have dropped shower traps as much as 3 feet under the shower base.

Good luck, Tom

Hi Speedball,

Thanks a lot for answering my question, I appreciate it. I have a follow-up for you:

1) I have read the max distance from p-trap to standpipe for the washer is about 42", this means putting it in the basement is not possible; that would be on the order of ten feet, a pretty hefty column of water rushing through the trap I think. So I guess it needs to stay on the second floor (1st floor belongs to someone else)

2) "What is the minimum distance that a waste tee must be above the top of a p-trap to ensure that water will flow through the trap and NOT up through the tee into my washing machine pan?

In order to insure the washer discharge won't back up into washer the waste tee for the pan would have to so high it wouldn't drain the pan."

Are you saying that I simply cannot use a tee to connect the tray that goes under the machine into the standpipe without the water rising up from the p-trap and into the pan? If so then I an confused as to how I can actually connect this thingy to the drain.

Thanks again for your help, I wish we could clone you and put you in every home depot...

-Bruce

1) I have read the max distance from p-trap to standpipe for the washer is about 42", this means putting it in the basement is not possible; that would be on the order of ten feet, a pretty hefty column of water rushing through the trap I think. So I guess it needs to stay on the second floor (1st floor belongs to someone else)
Max distance from trap to vent,( standpipes are connected to the trap as raisers) is 5' for 2" traps and 3 1/2' for 1 1/2". I think you're asking about the max distance between the top of the stand pipe and the trap. There is no limit on the height of the stand pipe although the minium from the trap is is 36inches.
2) "What is the minimum distance that a waste tee must be above the top of a p-trap to ensure that water will flow through the trap and NOT up through the tee into my washing machine pan?

In order to use the trap and drain line to drain the washer pan you will have to platform the washer up over the trap. Since this isn't practical you will have to run the washer pan drain outside or drain it into a floor drain.

3)I just read another related post and a different option would be for me to put the trap in the basement, I just assumed that would be way to far of a drop. Can I just do this and then add the proper venting close to the p-trap?

If you could lower the trap a few feet you could install the pan drain tee in the stand pipe with no worries. I have dropped shower traps as much as 3 feet under the shower base.

4)Are you saying that I simply cannot use a tee to connect the tray that goes under the machine into the standpipe without the water rising up from the p-trap and into the pan? If so then I an confused as to how I can actually connect this thingy to the drain.

That's exactly what I'm saying. If you connect it above the trap it will not drain and if you connect it below the trap you will have opened up a direct connection between your home and the sewer allowing sewer gas to enter your home. Let it go! Find another way to drain the pan or forget it.
Regards, Tom

Thanks Speedball, I appreciate your help. The trap stays on the 2nd floor, the pan gets drained another way, another day.

--bruce