[Over_Engineer_It]

I am looking for advice like the other two postings on installing a Dishwasher that is not geographically proximal to the sink. My difference is that I am going to install a new run with a P-trap and an AAV. My configuration is:

-The AAV 10” downstream of the trap. The AAV rises approx 14” from the run and touches the bottom of the insulation. The AAV is on 1½” PVC.
-Downstream of the AAV is 10' of 2" PVC at 1/4" per foot fall.
-On the upstream side of the P-trap is my 1½” PVC riser approx 10”.
-At the top of the Riser I have a 1½” to threaded ¾” reducer. I also have a ¾” threaded to 7/8” barb for which I plan to attach the drain from my dish washer. This connection is approx 10” below the bottom of the dishwasher under the floor joists.

My questions focuses on the fact that I have created a sealed environment on the upstream side of the P-trap (unlike a normal sink which has air access from the sink or a washing machine drain which does not completely seal the drain raiser) The questions are:

1) Will the system function correctly? i.e. the trap work without creating a siphon emptying the P-Trap?
2) Because the upstream side of the trap is sealed, would it work better to shorten the riser place a T where the barb would enter through the side and place an additional AAV above?

[speedball1]

"1) Will the system function correctly? ie the trap work without creating a siphon emptying the P-Trap?"
The AAV, (Air Admittance Valve) will break the vacume

"2) Because the upstream side of the trap is sealed, would it work better to shorten the riser place a T where the barb would enter through the side and place an additional AAV above?"

You speak of a sealed system but I don't see it that way. The pumps sump is open to the air inside the dishwasher and will be vented by it while the AAV will vent the drain.
It sounds to me like you ave things pretty much under control. Good luck, Tom

[guywithquestion]

Hi Tom, I have a similar situation, would adding the AAV on the upstream side of the trap cause any issues? I currently have a setup with an AAV on the downstream side, the trap is about 3' below the dishwasher (unit is on the 1st floor and trap in the basement) and it seems like water is being siphoned out of the dishwasher, will adding the AAV upstream near the point of connection to the dishwasher drain hose solve my issue or make it worse?

Thanks

Scott

[speedball1]

Hi Tom, I have a similar situation, would adding the AAV on the upstream side of the trap cause any issues? I currently have a setup with an AAV on the downstream side, the trap is about 3' below the dishwasher (unit is on the 1st floor and trap in the basement) and it seems like water is being siphoned out of the dishwasher, will adding the AAV upstream near the point of connection to the dishwasher drain hose solve my issue or make it worse?

thanks

Scott

Hi Scott, The AAV's installed doenstream from the trap, (see image) you already have a openingto air on the upstream side through the dsrain. Nothing would be gained by placing one on the upstream side. Tell me more about your set up. Why does your DW have a dedicated trap instead of draining into a disposal unit or branch tailpiece? What are you using for a air gap? A drip loop or a counter top air gap? ( see images) Let's hear back from you, tom