1. Two float-switch contact types are available: upper-level NO and lower-level NC. (a) Upper-level NO: the switch continuously sends a signal when the oil level is above the minimum limit. (b) Lower-level NC: the switch continuously sends a signal when the oil level is below the minimum limit.

2. When selecting a float, the liquid’s specific gravity must exceed the float’s specified minimum; otherwise, the float will not rise. Water has a specific gravity of 1, while typical lubricating oils are approximately 0.85–0.90.

3. For viscous liquids, a float with a larger outside diameter is recommended. As the liquid level rises, the larger float provides more buoyancy to overcome surface tension, reducing the risk of incorrect detection or a float failing to move.

4. A magnet inside the float actuates a reed switch. Iron particles in the liquid can therefore cause incorrect detection. Keep the liquid or oil clean.