Dishwasher won't drain after end of cycle
I can't get this dishwasher to drain at all, I have to pump it out by hand or it overflows. Each time I run a cycle, it leaves more water in the tub after the cycle finishes, starting with about an inch or so, maybe more. This has progressively been getting worse for about a month now, to the point where the unit cannot be used at all without recirculating old water and risking overflow.
I've checked and cleaned the sump filters and removed a few obstructions. I replaced the drain solenoid, which appears to be working correctly. Today I removed the unit from under the counter and disassembled the drain pump/circulation assembly and removed some obstructions from the impeller and surrounding pipes, including a random screw, and cleaned the filter around the impeller. I also removed and checked the drain hose, which did not have any clogs or apparent kinks. After reassembly I ran a rinse cycle and can see that the drain pump motor and solenoid are working during this time, but no water is drained. I've double checked that the drain hose has a high point under the sink before it connects to the garbage disposal, and I have checked to make sure there is no drain plug still installed in the garbage disposal. I've checked the float manually and it appears to be working, at least when I tap on it it goes down and pops right back up.
Short of taking a high-caliber rifle to it to see if that fixes the problem, I'm out of answers. Any thoughts are greatly appreciated.
Is this a good question?