Washing drain overflowing

[Twowaxhack]

Most of the homes in my area that were built in the late 50’s - the 60’s were piped with 1.5” copper above the subfloor for most fixtures except the toilets.

They would transition to 2” cast iron either at the sub floor or just below the floor or slab.

So you’d have copper stacks and traps and kitchen sink arms. The lavatories and tubs would also have copper stacks and brass traps.

Sometimes I’ll find 2” cast iron traps.

Some of this is still operational today and is working with washing machines of all types.

 

[MicEd69]

JWD, your original picture was for the far-left standpipe. Is the overflowing issue with just that one, or for all/most of them in the apartment complex?

From your recent picture, I see why you gave a range of 20" to 24" above the P-traps as there are several standpipes. And as you said, "When the washer drains, the water spills out almost immediately.", and that a full open hose does not cause an overflow, those statements appear to indicate that the issue isn't a blockage somewhere down the drain line. The far-left standpipe is properly vented, and my guess that the standpipe overflow is due to the fluid dynamics associated with the high pump out flow from the washing machine.

So, my original recommendation of making the standpipes as tall as your governing code allows still stands.

It would be helpful to verify the piping sizes of the standpipes and all the downstream drains. Current codes require washing machine standpipes and drains to be 2". The primary codes in use also say that the P-trap drain arm needs to be a minimum of 6" and a maximum of 18" above the floor.

And as Twowaxhack indicated, a double sanitee shouldn't be used in this application. But the middle standpipe is not properly vented as it now is installed. With the location of the drain line through the floor, that standpipe needs to be moved to the right so that a vent can be installed in the horizontal run between the P-trap and the drain. It can be tied into the existing vent above the top of the washing machines and standpipes.

 

[JWD]

JWD, your original picture was for the far-left standpipe. Is the overflowing issue with just that one, or for all/most of them in the apartment complex?



It would be helpful to verify the piping sizes of the standpipes and all the downstream drains. Current codes require washing machine standpipes and drains to be 2". The primary codes in use also say that the P-trap drain arm needs to be a minimum of 6" and a maximum of 18" above the floor.

And as Twowaxhack indicated, a double sanitee shouldn't be used in this application. But the middle standpipe is not properly vented as it now is installed. With the location of the drain line through the floor, that standpipe needs to be moved to the right so that a vent can be installed in the horizontal run between the P-trap and the drain. It can be tied into the existing vent above the top of the washing machines and standpipes.

My apologies for not replying sooner. I didn't get any email notifications of activity, so thought the thread ended.

The first one in the photo is the worst, but the one to the right in the photo will overflow as well, but it takes a bit and it doesn't gush out as strong. I've been a litte under the weather, but as soon as I am able I will pull the machines and get proper measurements and photos if needed. Thank you.