Ask Me Help Desk - Standpipe overflow

First let me say how impressed I am with this site and your willingness to help DIY'ers.

For some background;
We have a 30+yr old house designed and built by an old school DIY'er. Suffice it to say we have discovered some interesting engineering. He obviously had a good supply of 2" drill stem, as it is featured prominently in the build of the house and out-buildings. It is a split-level, walk-in basement on a slab which extends to side-walk width outside, with a septic tank.

The Washer (new Maytag Bravos Top Load HE) is on the walk-in wall where the floor is at ground level. The construction of the wall is paneling-studs-cinder block-brick inside to outside. The standpipe abuts the cinder blocks, shares the drain only with a sink on the same wall (junction is below slab) and is not connected to the septic system.

The top of the standpipe is 2" ID PVC (originally 32" high, that I extended to the manufacturers recommended minimum of 39") which (I learned after tearing out the wall) joins a metal pipe approx 1 3/4" ID (probably drill stem; see above)1 foot before passing through the slab, with no clean-out access to be found and no visible gray water discharge outside.

Problem;
With the old washer (it died) we could wash two loads back to back. On the third load it overflowed. Wait a few hours, repeat. Aggravating but manageable.The new washer overflows the pipe during the first drain of the first load.

The manufacturer calls for a drain carry rate of 17 GPM. At an estim. Flow of 4-5 GPM it takes a garden hose 3 min. to fill the standpipe.

So far I have tried chemicals, hot water and compressed air (while blocking adjoining sink drain) with no noticeable improvement.

The metal pipe through the slab and/or the prospect of metal pipe in the ground makes me wonder if snaking is a wasted effort.

Any suggestions regarding how to proceed OR best/easiest/most cost effective options would be greatly appreciated.

8up

Quote:

Originally Posted by 8up

bump

Sounds like the issue is most likely occurring where the line is telescoped.

You should consider upgrading the entire line to 2" (standpipe, trap, trap arm and drain.)

I agree with Growler that your drain's undersized for the more powerful Maytag pump. We have had many complaints about the new Maytags overflowing. Growlers suggestion is the best possible one but it's also expensive and involves major surgery. Why not install a compression fitting,(see image) on the standpipe and close off the opening so it can't overflow.
I have had one on my standpipe for years with no problems. The feed back we get from the people that have installed them all say the overflow's gone.
The only other solution, besides replacing the washer trap and drain, would be if Maytag replaced your washer with one with a less powerful pump.
They did that with a lady that had bought one and had the same problem that you have. Goog luck, Tom

Quote:

Originally Posted by speedball1

I agree with Growler that your drain's undersized for the more powerful Maytag pump. We have had many complaints about the new Maytags overflowing. Growlers suggestion is the best possible one but it's also expensive and involves major surgery. Why not install a compression fitting,(see image) on the standpipe and close off the opening so it can't overflow.
I have had one on my standpipe for years with no problems. The feed back we get from the people that have installed them all say the overflow's gone.
The only other solution, besides replacing the washer trap and drain, would be if Maytag replaced your washer with one with a less powerful pump.
They did that with a lady that had bought one and had the same problem that you have. Goog luck, Tom

Thank you all for the responses and your expert advise. I want to avoid a new pipe if at all possible, as that would involve going through/under/around the slab.
I thought snaking would mean digging up the line outside because I was worried the snake wouldn't make the 90 dg. Turn down the standpipe, but have been told that it should be OK (no roof vent or clean-out access).
If snaking doesn't work I think the compression fitting will be the next best option.
I assume I would need to install a shut-off valve of some type between the standpipe and the neighboring sink to prevent back flow? (see OP for layout) Will that work in theory?
I am snaking tonight. I may find the metal pipe is shot, which will at least settle the argument about how to proceed.
Thanks,
8up

If you install a compression fitting on the standpipe a check valve should not be needed between the stand pipe and the sink. I take it that this is a laundry tray. If you get any backup in the sink, (which I doubt) just buy a rubber stopper and close off the sink when you run the washer. Your snake should make it around the return bend in the trap with just a bit of cranking and pushing. Good luck, Tom

Quote:

Originally Posted by speedball1

If you install a compression fitting on the standpipe a check valve should not be needed between the stand pipe and the sink. I take it that this is a laundry tray. If you get any backup in the sink, (which I doubt) just buy a rubber stopper and close off the sink when you run the washer. Your snake should make it around the return bend in the trap with just a bit of cranking and pushing. good luck, Tom

Update;
The snake would not make the turn at the bottom of the standpipe, which leads me to believe there are pipe issues in the ground.
I can run a garden hose for four minutes before the pipe overflows, but I guess the only way to find out if it is going down the pipe (and not under the slab) is to start digging. Weeee!!
I will update.
Thanks again,
8up

Are you on septic or city sewer? Many septics can't take 3 loads back to back but it should take one load even from a Maytag. Follow the advice of Speedball and Growler.

Quote:

Originally Posted by ballengerb1

Are you on septic or city sewer? Many septics can't take 3 loads back to back but it should take one load even from a Maytag. Follow the advice of Speedball and Growler.

Thank you for your advise.
The standpipe is on its own line.
Quoting OP;
"The Washer (new Maytag Bravos Top Load HE) is on the walk-in wall where the floor is at ground level. The construction of the wall is paneling-studs-cinder block-brick inside to outside. The standpipe abuts the cinder blocks, shares the drain only with a sink on the same wall (junction is below slab) and is not connected to the septic system."

Thanks,
8up