LIQUID LEVEL SENSOR

Interesting, but...

This is an odd little level sensor. The first odd thing is that the internal magnetic reed switch closes when the float moves to the end of the rod with the wires, not the other end as in the description. The second odd thing is that the switch closure is not consistent, at least not on my two samples. The switch closure seems to depend on the orientation of the float--rotating it around the rod when at the end nearest the wires (what I consider the 'top') will sometimes close or open the switch. Not very repeatable, and not something that you can trust will work every time the float moves to the top position.

If I had to guess, either the internal reed switch is mounted just a little too close to the top end of the rod, where the magnet in the float can't quite reach to close it every time, or the float magnet is a bit weak. There's a small raised shoulder on the top end of the rod that keeps the float from moving closer to the top. I will remove this shoulder with my lathe to see if getting the float about .100" closer to the switch location will make it kick the switch every time. If not, well, I think I'll look elsewhere for a more reliable level sensor.