I have an update. And BTW, like I said earlier, I always keep the sump clean. And in this case, the sump was spotless and the impeller is fine. I'm not trying to be a jerk. Its just that this is the third forum I've gotten on looking for help and every time I keep hearing "clean out the sump" as if that is all anyone knows about. I'm not trying to put you down as I see you have a pretty good reputation. But lets get past the sump.
Here's what I've come to learn.
I tore apart the water distribution system. On top of that distribution system is the water inlet switch. It is a pressure operated diaphram. As the water level rises air is pushed up into the thing and a diaphram pushes out on an actuating rod that clicks a switch. The first time the switch clicks the washer starts running and the water level drops. It continues to allow water into the tub and the second time it clicks water flow into the unit is stopped.
The red thing I spoke about earlier does not control the drain pump. It is an overflow device. After the washer was running I took and poured a gallon or so of water into it which made the float rise and start the pump. Once the float dropped to the proper level the drain pump stopped.
I then sat there and watched the stupid thing. Great way to spend a Saturday eh? When the pre-wash stage ended the pump kicked on and drained like a banshee. It drained for a good 30 seconds like the book says it should. When that finished I opened the door and it was empty. After closing the door it started filling once more with clean water.
So I'm stumped. This time all worked well. Last time it didn't. This is what I mean by intermittent. I didn't fix or clean anything. All I did was
- disconnect the plugs to the fill switch and overflow draim pump switch
- take apart the input control thingy (to understand what it did)
- put it all back together and run it again
That's it. So what controls the pump at the end of the three stages? Whatever does that is the culprit. Either that or the impeller sometimes just can't pump. But I don't think its the impeller. It spun just fine and the problem is that it can't pump, its that it doesn't pump for very long.