Drain Water in Diswasher

[DaveC1]

Hi, I had a kitchen sink blockage that sent drain water into the Dishwasher. While I don't have an air gap, my Diswasher drain hose comes from the disposal and loops up along side the sink(at least 6 inches above the bottom of the sink). The backup occurred while my wife was doing dishes and the level in the sink never exceeded 1 inch. Is there a scenario I am missing that would have put drain water over the loop and into the Dishwasher?

 

[Breplum]

Running a disposal can cause water to literally pump creating positive pressure in the garbage disposal zone. In your case, there is also a failure of the drain solenoid to seal properly.
This is the reason that 'smart' codes like UPC require DW air gaps...not optional like dumber codes.
Here is an example I witnessed: Customer complaint that when she runs the disposal water comes out of ceiling light fixture.
1. Clogged kitchen drain
2. Disposal created positive pumping pressure
3. Kitchen sink vent had a leak in the general area of the light fixture.
I don't recall the cause of the vent leak

 

[Sponsor]

 

[DaveC1]

Running a disposal can cause water to literally pump creating positive pressure in the garbage disposal zone. In your case, there is also a failure of the drain solenoid to seal properly.
This is the reason that 'smart' codes like UPC require DW air gaps...not optional like dumber codes.
Here is an example I witnessed: Customer complaint that when she runs the disposal water comes out of ceiling light fixture.
1. Clogged kitchen drain
2. Disposal created positive pumping pressure
3. Kitchen sink vent had a leak in the general area of the light fixture.
I don't recall the cause of the vent leak

Those are good tips bro and I agree about the air gap..... Interestingly, we don't use the disposal so the pressure couldn't have come from that.... pressure came from some where though!Thanks again, Dave