No existing p trap on washing machine

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mjhamel

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My wife and I just moved into a house in the country. There is a first floor laundry room where we have put our washer and dryer. We have noticed a sewer gas smell and think it is because there is not a p trap installed on the washing machine drain pipe. There is an elbow near floor and then an approximately 3', pvc pipe (4 inch diameter) that is used for the drain pipe.

The elbow leads directly outside, where there is another elbow that runs down into the ground and into a pipe that leads to our lagoon.


I'm unsure how to correctly install a p trap in this instance. The 4" pvc pipe is kind of throwing me for a loop as well as the lack of space to install something. I am new to plumbing, so if anyone has any advice on what I should do, I would great appreciate it! Thanks for your help and let me know if you have any further questions.
 
If you can dig down a few more inche's into the soil outside AND if you can raise the horizontal section of pipe that penetrates the wall, then you could cut out the exterior elbow and remove everything in the wall and the piece where your discharge hose drains your snide the house.
Next, install a tee on the exterior point of connection making sure you have installed it high enough to allow for your p-trap on the inside to be clear of the floor (you may need to use a coupling and a short piece of pipe to get your height on the exterior connection before you install the tee), make your tee installation with the branch of the tee going into the wall so you can assemble the p-trap and trap arm from inside and into the tee's branch.
Now you just add a riser to your p-trap for your discharge hose and finally, run a vertical vent from the top side of the tee up, along the exterior wall ( best if you can make it terminate about 12" above the roof).
Now you have a properly vented and working waste line for you washed.
 
Looks pretty good.
Here is a little guide for getting the positioning right:
tumblr_n62q5oltZD1qkwd9ao1_400.gif


Looks like what you sketched, but apparently the measurements are rather particular.
 
frodo said:
because of he powerfull pumps in todays washers, try and get that p trap as close to the floor as possible. your stand pipe needs to be as tall as you can get it.

if it was me, sit that trap on the floor and make the stand pipe 24" tall
Click to expand...

Does code permit it to sit on the floor? Or would it work to have it 6" from the floor and then have it go up 18"+ ?
 
it can sit on the floor, you just dont want to have it so high that your stand pipe is short.

the shorter the sand pipe, the more likely you will get suds backing out the top. at a later date

the minimum you are looking at,in the drawing, is the trap arm, not the trap. the trap goes down from the trap arm

answer your question, there is no code concerns [that i know of] against trap on the floor.
 
frodo said:
it can sit on the floor, you just dont want to have it so high that your stand pipe is short.

the shorter the sand pipe, the more likely you will get suds backing out the top. at a later date

the minimum you are looking at,in the drawing, is the trap arm, not the trap. the trap goes down from the trap arm

answer your question, there is no code concerns [that i know of] against trap on the floor.
Click to expand...

Thank you for clarifying that, Frodo!
So as long as the trap arm is in the right size range, it can sit on the floor and the standpipe can be tall? I wonder where the measurements in the diagram originated. I just found it online somewhere, but I've seen some diagrams that were flat out wrong. Does the standpipe top have to be below the level where the hose comes out of the washing machine, or is there enough pressure in the washer to push water slightly up? I know most fixtures drain with gravity, but I've read/heard that washers use pressure instead.
 
No. For most fixtures, the maximum distance from the fixture outlet to the top of the trap is 24".

There isn't a definition for standpipe in Chapter 2: Definitions, so I am just thinking that this applies to fixtures that discharge indirectly into a riser on a trap, such a 3 compartment sinks, laundry machines, etc.
 
but, the 24" code is for fixtures, correct?
a washer or washer box is a fixture. so would not the 24" rule apply to the stand pipe for that fixture?

that has always been my understanding. but hey,,,teach this old dog new tricks

this is upc..not ipc 1001.3 and 1001-4. i know ipc let you do any damn thing! lol

scan0007.jpg
 
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Found this in Louisiana plumbing code:
I. Distance of Trap Weir from Fixture Outlet. The
vertical distance from the fixture outlet to the trap weir, or
from the outlet of an integrally trapped water closet or
similar fixture to the horizontal piping connecting the fixture
to its vent, shall not exceed 24 inches (610 mm).
1. Exception. Washing Machine Pumped Waste Drain.
The vertical distance from the vertical standpipe inlet
receiving the pumped waste discharge from a washing
machine (laundry) to the trap weir shall be a minimum of 30
inches (762 mm) and a maximum of 48 inches (1219 mm),
with the vertical standpipe inlet terminating a minimum of
34 inches (864 mm) above finished floor or in accordance
with the manufacturer's recommendation.
AUTHORITY NOTE: Promulgated in accordance with R.S.
40:4(A)(7) and R.S. 40:5(2)(3)(7)(9)(16)(17)(20).
HISTORICAL NOTE: Promulgated by the Department of
Health and Hospitals, Office of Public Health, LR 38:2867
(November 2012).

Granted, that might not apply to other states. I think Louisiana code is based on IPC.

Editing to remove my comment about cleanouts since I mis-read something. From my understanding a cleanout is required for the pipe after the trap, but not in the trap or before?
 
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Anotherwords, if you noted the two exceptions, You could have the riser for a floor mounted toilet 6' long if you wanted to, and then run 50' to it's vent.
 
No gurgles at all, whatsoever.

Think about it, the reason for the restriction on trap arm length is to prevent the trap from siphoning itself. A toilet is designed to siphon the trap, so as to remove the waste from the bowl. What does it matter, then, how far the toilet is from it's vent? The only reason a toilet needs a vent is to prevent it from either siphoning or blowing out another trap, or being siphoned/blown by other fixtures. For that, it doesn't matter how far away a vent is.
 
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