washing machine drain pipe overflow

[stephencc]

My clothes washing machine drain pipe overflowed water when the machine was emptying, so I augered the pipe over 15 feet and I even had a plumber do the same while he was there for something else. But when I poured water into the standpipe to check it before using the machine again, the water came up to the top and stood there. So I augered it again and the same thing happened when I checked it again.

Then I noticed that if I simply put the 'snake' straight down the pipe with my hand until I reached the P-trap, the water level went down, if not all the way to the P-trap then at least close. This was despite the fact that there was no resistance and nothing on the snake when I pulled it out. Yet when I poured water down the pipe again, it still rose back up and stood. So I was baffled by that.

And then I noticed that the water level was stopping at the place in the standpipe where a pipe branches off at an upward angle towards the A/C unit. And so I poured more water down the pipe and somehow the water level didn't rise, it started going up the inclined pipe towards the A/C unit, which seemed to defy physics. I again pushed the snake down the pipe by hand with no resistance just to the P-trap and the water went down right away to at least close to the P-trap. So I am completely confused.

I would really appreciate any thoughts on this. I am still afraid to use the washing machine until I can add water to the drain pipe without the water level coming up, which is how I had checked it before when I had problems in the past without this strange result.

Thanks for any advice or information!

 

[Deleted member 120897]

Where does the standpipe terminate? Has this been checked? Have you dismantled the p trap? The water going up the inclined pipe, if the othe water has nowhere to go then it will find its own level, so will go up the inclined branch pipe.

 

[stephencc]

the standpipe goes into my floor and into cement before it even gets to the p-trap, so I cannot see or work on it. It is an old building apartment with copper pipes, though the standpipe is pvc.