I believe the check valve is bad as gray water fills in tub even when dishwasher is not running. This happens when I have any slight blockage in sink trap or disposer out pipe. Do you think that this is my problem?
The check valve being defective can certainly cause the back flow into the unit. You would need to check it for damage. Also check to make sure that the drain hose has a loop in it as an air gap.
Answered by AppliancePartsPros.com | Tuesday, April 02, 2013