Washing machine overflow

[tkelle]

When I run the washing machine and the water is draining, I hear a gargling sound coming from the kitchen sink and then the sink will fill with water and the drain for the washer will overflow. I have ran a snake through the washer drain and through the drain under the kitchen sink and I met no resistance. I have also tried foaming clog removers.

It appears the washing machine runs under the floor to the drain for the kitchen sink. The kitchen sink drains have a "cleanout" on the 6" pipe coming out of the floor.

Any suggestions??

[HayZee518]

are the pipes that drain your kitchen sink connected to a "stack" above the drain lines? This "stack" provides air to help your system drain. If not then the drain is trying to suck air from someplace within the drain system

[tkelle]

The stack stops just above the drain connections for the sink. There does not appear to be any venting.

[LazyPup]

Was the laundry and kitchen drains original to the structure or was one added later? Sight unseen I would guess that the line is both too long and too small.

By code pipes must be sized by the total load.

A kitchen sink is rated at 3 DFU's (Drainage fixture units).
A washing machine standpipe is rated at 2DFU's (International residential code-IRC.) or 3 DFU's (Uniform Plumbing code-UPC)

The combined losd is either 5 or 6 DFU's depending upon which code you referenence.

A 1.5 inch line is limited to 3 DFU's.

Under the IRC an 1.5" drain line may run a maximum of 6ft (UPC= 3'6") from the trap wier to the vent.

Increasing the horizontal pipe from 1.5 to 2 inches would allow 6 DFU's under the IRC or 8 DFU's under the UPC and would permit a maximum run of 8ft(IRC) or 5ft (UPC).

Depending upon the actual layout, you may need to increase the underfloor horizontal line to 2" diameter and install an auxillary vent near the far end of the run.