Overflowing washing machine

Hello,

I am redoing my kitchen. The washing machine drain used to be a stand pipe 1" 1/2 width about 5ft 1/2 high going directly to the cast iron 2" drain of the house, no trap.

I will describe what i have now instead which is also on the picture, much easier to understand.
I had to change the drain location to be 1 foot away. I removed the cast iron elbow and switched to PVC 2". Still in the ground, PVC 2" goes to 1" 1/2, I added a trap and relocated the stand pipe 2ft further ad i had to short it, it is now about 4ft. To compensate the shorter stand pipe, I put 3" PVC for the stand pipe.

The washing machine is now overflowing on cycles that used to be fine before. Before the changes sometimes we would have a little overflow in the kitchen, very minimal.

What do you guys suggest to fix this overflow situation?

Thanks all

 

You added a trap without venting it or you have a blockage. A p-trap without a vent will slow the water flow down.

 

Welcome to the forums.

I enlarged the picture to show the washer detail. Can't read your text.

You've created a bottleneck with that trap. The piece of 3" pipe can maybe hold a gallon of water but it does nothing for improving the overall drain flow. All that plumbing is draining into a 2" pipe in the floor ?

 

You said you had a little overflow before. You have to clean the drain line all the way to the street. Washers dump a lot of water in a hurry and any blockage will show up.

 

Hello Pjmax,
Thanks for the input.It is correct when you say all the plumbing goes into a 2" part on the floor. At least from what i can see, I know the washing machine goes into a 2" cast iron, as well as the sink. I assume they end up going into the same main drain because of where the septic tank is located. Now, it is possible that it goes to a bigger pipe before or after the 2 drains join together.

Hi Pugsl,
Thanks for the idea. I plan on doing that for sure but i was just surprised of how much it overflows now compared to before...

 

Are you sure all the piping under that 3" pipe is 2", it looks like 1.5" from here. It really needs to be 2" all the way from the standpipe to the drain. Also, the p-trap setup looks very odd and likely not correct. In addition, having the washer trap above the sink trap will likely cause the sink trap to be sucked dry - you're creating a wet vent in that configuration. And I can't see how the vent is connected which may be causing some problems too.

 

Hi Zorfdt,
Underneath the 3" it is 1"1/2 yes. Also the washer trap is slightly lower than the sink trap, which is not on the enlarged picture. The lowest trap on the enlarged picture is nothing anymore, i closed it. I was going to have the dishwasher here but more research made me want to have the washing machine on its own. Finally the vent pipe is actually right in the middle going straight up after the trap.

HOWEVER,
Before starting new plumbing work last night i went ahead and try the new washer we got and put it on heady duty load. It went all well. I can hear by the sound it makes that the discharge of this washer is a little slower than the previous one I had. I am going to try a few other cycles. If it does not overflow I will think I am good to move forward

 

A new washer is most likely a low volume washer. 6 to 8 gallons compared to 25 + on old ones. Less likely to back as fast.

 

Since you have the 2" drain in the slab, you really should replace that whole section with 2" pipe to bring it up to current code. The vent can remain 1.5".

I would probably install a cleanout too just to make it easier to snake in the future. With older piping, I'm sure it will be needed at some point within the next few months/years.