Washer Drain Pipe

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knix98

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Hi,

My washer drain pipe keeps overflowing. I tried snaking it but a clog does not seem to be the problem. I think it may be the setup. If you look at the picture originally the standpipe was 9 inches (which was only slightly longer than the pipe leaving the trap) I thought this maybe be the problem so I extended the stand pipe by 24 inches, but this has not helped at all. Seems as if the water is getting stuck at the trap not sure though. Any suggestions? Thank you in advance!

drain.jpg
 
Welcome a- board :D
It really looks like a trap,,, but it isn't. This is probably the issue. The water being forced into the standpipe, just cannot handle the volume.
 
Force hot water into the pipe for a solid minute. If the water comes out on your roof there may be a clog, probably from lint.
Repeat for the roof vent but with helpers in the house watching for overflows.

Fill your washer with a known quantity of water and then select the drain part of the cycle. Check how long it takes to empty.
This will give your gallons per minute flow rate and this number should be compared to the posted capacity of your (1-1/2" ID?) drain pipe.
 
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I have no clue on this but has all the markings of a DIY trap setup and most likely doesn’t have a stack in the line or if it tees into another line that stack is too far from the homemade trap to do any good.

Water will chug down a line like that but without being able to get air in behind it will never flow fast. Compare it to pouring from a gallon jug where the air coming in has to pass the water going out when you hold the jug straight down, now poke a hole in the bottom of the jug and try it with a vent hole to let the air in.

That homemade trap is fine and doing its job by keeping sewer gas from coming back. It’s also doing a second job of not letting air go down the line the water moving down pulls a vacuum on the line trying to suck the water out of the trap but new water keeps sealing it off. Thus the slow flow and acting like it’s kind of plugged.
 
I really don't know anything about plumbing so Im not sure where the stack is or if there is a stack. The drain pipe goes into the basement wall which is about 6-8 feet away but uses probably 10-12ft of pipe since it encompasses two walls. Somebody suggested that the trap was too deep so I cut it to make it shorter but that did not help the problem at all.
 
The stack is a pipe that runs up to the main floor of the house to pick up other drains and continues thru the roof for a vent. Without a vent the water running down the pipe will vacumn the water out of the trap and allow sewr gas into the house like there was no trap. There is a limit to how long a run can be befor you have to add another pipe freom this one up and over to the stack so air can get behind the water and stop the vacumn. 12 ft would be way past that limit. Some set this up and likely made the oversize trap to help with that problem.
All this may be over simplified but now I hope you can have a look around and see what you have. You also want to check the slope of the pipe. Old a level up to the pipe and hold it level and see how far the pipe is off level. 1/2" with a 2 ft level would be 1/4" per foot slope.
 
That high vertical pipe should take care of level problems.

At this point I'd try to take a peek at a copy of the plumbing code at a tech bookstore. The plumbing code excerpts in my copy in the IRC 1999 are pretty detailed and pretty complicated. When I added a bathroom vanity I almost had to reroute the pipes in the wall.

The designers of the OP's system may have also run up against nasty problems and that system may represent their compromise; they did the best they could without tearing down walls. They gambled.
 
try this...
Yeah, that's kind of what I ran into. And IIRC that 4", 5" segment had a downslope.
The problem was the vanity sink was not exactly the same height as the original wall hanging sink.
And, since it was a three dimensional problem, locating the holes on the back wall of the vanity was beyond my two dimensional thinking.
 
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try this...

That would be great except this thing is five feet off the floor for a reason.
I doubt if code is his first worry. He would be looking at sumps and pumps and big dollars. If the main line is not plugged and the 12 ft run was sloped good. he could try to install a cheater valve to suck air. He just wants to do the laundry.
 
I guess a booster water pump could overcome piping design problems and maybe partial blockages but I've never heard of a pump being used this way.

An analogy would be a ductwork booster fan.
 
Without knowing where the line runs to its hard to tell if he even needs a trap for that matter. Around here a lot of people have washing machines going to a dry well. Others run them to a ditch etc. it's very common to have them bypass the septic tank and go to what we call a grease trap along with the kitchen sink and then joins the grey septic water into a leach field.
As Neil suggested a cheater vent might do the trick here. Or maybe a little stack up and thru the wall. None of that is code and depends on what's on the other end of the pipe.
 
Did some measuring the first pipe is sloped 5 inches over 6ft then the next pipe is sloped 4 inches over just a little less than 6 ft. The whole thing starts 52 inches off the ground and ends inches off the ground. A cheater vent would just a be a straight vent sticking out somewhere along the pipe line? How far down the line would I put this?
 
Was just looking at exactly that....appears that the vent should be close to the trap.
To see ahead of time if a vent will work you could snake a tube down the pipe that allows air to enter.
If no change it's likely a clog.
 
To see ahead of time if a vent will work you could snake a tube down the pipe that allows air to enter.
If no change it's likely a clog.

Ok Ill try that. Looks like most places have the vent close to standpipe but wouldn't it be more beneficial to be a little bit down the line more since some air is entering through the standpipe?
 
Ok Ill try that. Looks like most places have the vent close to standpipe but wouldn't it be more beneficial to be a little bit down the line more since some air is entering through the standpipe?
Dunno'.
The more I think about the design of plumbing systems the more I realize I don't fully understand it.
For your answer I'd think you have to look in one of those fat, thick, little handbooks for residential or commercial plumbing design that Border's used to have. Barnes & Noble doesn't seem to be as good on this count.

For HVAC there's ASHRAE. Maybe there is a similar org. for plumbing design/engineering.
 
No air is entering thru the stand pipe. That's the problem. Just like a water trap keeps sewer gas from coming back up a pipe it also stops air from going down the pipe. A cheater vent allows the low pressure caused by the water running away to open and let air in to allow the water to flow out. Once the flow stops the flapper closes keeping gas from coming back up. These work but if the fail open then you fave gas. The best venting is a pipe that travels up to the roof line where the gas isn't a problem.
 
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