Drain design with stack in middle of 2 sinks + washer

[Tangerine]

I am adding a washer in the closet in the foreground. 3" stack is in the middle. Kitchen sink on right. Bath vanity on left. Washer can go on either side. All within 24" of stack so no separate venting.

1) Can I run both sinks using the dual fixture sanitary fitting (with bushings for 1 1/2 and 2") and get the drain heights to work?

2) should washer santee go above or below sink fitting? Cleanup above all of them?

Advice wanted...

 

[Terry]

You can't wet vent kitchen sinks, laundry sinks or washers.
Wet venting is for bathroom fixtures like lavs, shower, tubs.

A double san cross like that allows the water to skip across the fitting. It's also tough to snake, though I do see that you plan to install a cleanout above that.
The best bet would be to vent the sinks there, and tie back to the main vent at 42".
Then the washer could go above and use the center vent, as long as the sinks have their own vents. We're talking just a few more fittings and pipe.

 

[Sponsor]

 

[Tangerine]

You can't wet vent kitchen sinks, laundry sinks or washers.
Wet venting is for bathroom fixtures like lavs, shower, tubs.

A double san cross like that allows the water to skip across the fitting. It's also tough to snake, though I do see that you plan to install a cleanout above that.
The best bet would be to vent the sinks there, and tie back to the main vent at 42".
Then the washer could go above and use the center vent, as long as the sinks have their own vents. We're talking just a few more fittings and pipe.

Okay...Do I skip the double san cross UNLESS I install new vents...or simply skip them no matter what? I am not clear on what you are proposing. What is "...vent the sinks there." Where is there?

 

[Cacher_Chick]

This is commonly misunderstood, and not too easy to explain in layman's terms.

In your plan, only the top-most connection on the stack is properly vented. Any fixture connected to the stack below that must be vented by a separate vent connection.

Seperate fixture vents may be combined, but the connections must be made at least 6" above the flood rim of the highest connected fixture, and no less than 42" above that floor.

 

[wishiwasarealplummer]

Can I use a "double sanitary tee-wye 1/8 bend" for the kitchen and vanity sinks...and NOT vent them since they are only 20" from the 3" stack? (The long 90 for the washer is turning the corner horizontally...not heading down.)

 

[Reach4]

3" stack is in the middle.

Is that 3 inch PVC carrying drainage from the floor above?

 

[hj]

All of this assumes there is not plumbing draining into the 3" stack from an upper floor. NO, you cannot use either sanitary cross OR double combo for the connection IF you do not have vents on the lateral lines. You would need a "back to back fixture fitting" to make the connections.

 

[wishiwasarealplummer]

Is that 3 inch PVC carrying drainage from the floor above?

Just a vent...single story home with nothing above.

 

[wishiwasarealplummer]

All of this assumes there is not plumbing draining into the 3" stack from an upper floor. NO, you cannot use either sanitary cross OR double combo for the connection IF you do not have vents on the lateral lines. You would need a "back to back fixture fitting" to make the connections.

Are you saying a "back to back fixture fitting" (Canplas 194155 PVC DWV Double Fixture Fitting) would NOT need to be vented if it is within 20" of main stack and there is nothing draining above?

 

[hj]

"Normally" it would be okay, but EVERYTHING depends on exactly HOW you are installing the piping. It is risky to make a blanket statement without seeing everything involved.