Washing machines, and what’s missing

My washing machine recently overflowed.  I thought I’d located and repaired the source of the problem by JB Weld’ing a hole in the inlet valve incurred from washing a very large comforter (that’s another story), but that does not appear to have been the case, as the JB Weld held and we had another large puddle today.  That started me not only tearing apart the machine again, but considering all the things that have been left out of a modern washing machine to prevent this very kind of problem.  This particular machine was purchased somewhere around 2003, so perhaps things have changed since then.

After disassembling the machine and finding no obvious leak sources, I came to the conclusion that the water level sensor must be experiencing intermittent problems.  Testing with a multimeter per the instructions at http://www.acmehowto.com/howto/appliance/washer/check/waterlevel.php would indicate that the switch is good, but a little further playing around (testing, whatever you like to call it) may have provided clues to the intermittent nature of the problem.  Blowing into the pressure port on the switch generally triggers the audible “click” and corresponding resistance change between terminals of the switch.  However, I discovered by repeatedly blowing into the pressure port that the switch seems to intermittently stick and not click over.  Even this isn’t quite consistent with the behavior we experience with the machine, as it does seem to eventually kick over to the next cycle, but it’s enough in line that I believe it’s probably the source of the problem.  I could replace the switch – which I will – and the problem would be solved.  For another seven (Two? Ten? Who knows!) years, and then I’m back to teardown and trace again.

Whether or not I get around to it remains to be seen, but there were a couple of ideas that came to mind as a result of the leak.  First off, at the very least, the machine should have a water sensor that would trigger shutdown of the system upon detection of water.  From the factory, this should be simple and basic, and I would not expect it to require more than $10.00 – 15.00 in parts, as I think I can buy the needed parts as a consumer at that price.  Second, and more advanced, it should be possible to create a straightforward state diagram that would allow even greater control of the behaviors of the machine.  I’ll flesh out my idea on a kill switch first, since that should be pretty straightforward, and then if I have time I’ll proceed with thoughts on the state diagram and what would be required.

What’s required

• Water sensor, such as this one (I purchased one of these from Amazon in ’09; fortunately, it’s never needed to go off).

Note:  This is another one of those posts that I started once upon a time and never got back to finishing, but the good news is that I was able to fix the problem very simply, and it wasn’t a problem with the switch.  There’s a small box down low on the tub at the other end of the tube running to the switch.  One of the techs at the local appliance repair store suggested pulling the tube off at that end, and that I would likely find some gunk plugging it.  He was absolutely correct, and digging it out with a toothpick/blowing through the tube from the top end bought me another good year of functionality without a problem.  And the next time it overflowed?  Same problem, same fix.  Haven’t ever gotten around to the kill switch sensor, but we did leave the water sensor on the floor next to it and it has helped a couple of times.