, the complaint was the unit would leave water in the tub after a wash cycle and the customer would need to press the cancel button several times to get all the water out. Obviously something is up with the drain system on this dishwasher so that is where I started.Looking for the Problem
This line of tall tub dishwashers use a separate wash and drain pump which improves operation and in my mind, makes trouble shooting drain issues much easier. I start by pressing the cancel button to begin a drain cycle and checking the drain pump for operation. It is usually possible to tell if the pump is working, simply by listening to it operate, which this one was doing. But the problem was, very little water would run out of the drain pipe. This is often a sign of something stuck in the hose restricting the flow of water and can be the result of improper installation, or more likely, poor pre-wash habits of the users. But after removing the drain hose (and spilling water everywhere) I found the hose to be clear with no restrictions which left the pump itself as the likely problem. About this Pump
Many of these drain pumps are simple 110vac pumps that use a small plastic impeller mounted to a permanent magnet rotor assembly which slips into a watertight housing. The motor windings make up the stator portion of the motor and are wrapped around this housing allowing the motor to operate (the plastic doesn't interfere with the magnetic field of the motor) and keeps the water separate from the electricity. The motors are very reliable and quiet in there operation.What went Wrong
This particular pump sounded just fine, but because it was the likely failure, I pulled it from the dishwasher and removed the cover so I could get to the impeller itself, and that is where I found the problem. The impeller which is mounted to the rotor via a metal shaft was loosely attached and I was able to turn it while holding the magnet steady. So it looks like as the motor is running, the resistance from the water was causing the impeller to slip resulting in a slow pump out of the tub. Not a real common failure, but undoubtedly the result of something hard allowed to get into the sump. Once it made it to the drain pump housing, the impeller probably kicked it around until it finally flushed it from the drain line, but not before doing some damage. It is for this reason I tell people if they find a glass or dish has broken inside the dishwasher, find the broken pieces, or the dishwasher will do it for you.
The repair was accomplished by simply replacing the pump assembly with a new one as there are no serviceable parts for these pumps. With a new drain pump, this dishwasher was draining water again without needing an extra cycle.
Frigidaire Dishwasher Drain Pump Part # 154580301