My reputation as someone who can solve household engineering problems has spread over the years, and so I get requests for help with all kinds of household difficulties. A recent problem involved a washer. When the wash cycle was complete, the machine was still full of dirty water. I was called in to fix it.
In order to see exactly what was happening, I started a new wash cycle. First I had to set it to the start of the rinse cycle to pump out all of the dirty water. As it pumped out the dirty water into a washtub, I noticed the washtub was draining very slowly. So I figured the drain needed to be cleared. When I started the new wash cycle, it ran correctly. At the end of the wash cycle, the water pumped out to the washtub, and the rinse cycle began with clean water rushing into the tub. Yet at the same time, water was also being pumped from the full washtub back into the washer. That was when the revelation came.
Some washers, including this one, have a flow reversing valve on the drain pump, so when the water is not supposed to be draining, the pump discharge and inlet port connections are reversed, providing for wash water circulation. That would work out very well if the drain hose was above the surface of the water, which is the standard setup.
This setup was different. There was an extension on the drain hose, which was added to prevent the discharge flow from spattering out of the tub, all over the wall, and on to the floor. That extension, combined with the tub full of water, provided a handy means to draw the dirty water back into the tub. There was no overflow, because the level switch was satisfied and shut off the clean water valve.
The same cycle would happen when it went into the spin mode, at which time it would once again pump the water back into the tub during the spin cycle. So at the end of the wash sequence, the clothes were still soaking in the dirty wash water.
The solution was simply to clear the washtubs drain and add a small hole in the extension tube, so that the pump could not pull the dirty water in the next time the drain became plugged. The fix wound up being a lot less work than anything that I would have needed to do to the washer.
This entry was submitted by William Ketel and edited by Rob Spiegel.
William Ketel graduated from Lawrence Institute of Technology as an electronic engineer and quickly got involved in the testing area of automotive engineering at Chrysler. At Sun Electric, he learned controls and instrumentation engineering. He also picked up mechanical engineering and machinist skills and developed a love for designing industrial testing systems. For fun, he rides his bicycle and participates in ham radio activities as N8QVS.
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