1. If switch or switches do not seem to be working, measure each switch with an OHM (resistance) meter. When ohms measure zero, switch is closed, when ohms measure infinite or over 2 MEG OHMS, then switch is open.
2. Move float up and down and take ohm measurement for each switch to determine if switch is turning on and off as desired. Be sure to confirm that the wire color matches the level switch being tested. If OHM reading is not correct, sensor is not operating properly. Potential reason for the sensor not operating correctly is:
Float is not positioned properly or moving properly: Float clips (or collars) may have come loose, have been moved or not in the proper place. Inspect for debris or build up on the floats that would prevent them to move properly.
Shock or damage to the floats or the sensor assembly (bent, dented, etc.). Sensors need to be handled and installed with care. Check to make sure shipping container was not damaged. Internal reed switch has hermitically sealed glass housing that can break. Floats have magnets inside that can break or become dislodged from rough handling or significant shock or vibration.
Excessive moisture around the wires where they exit the sensor. This typically results in a switch not turning off (staying closed).
Reed switch failure: This can happen when high voltage or current (or a short) is connected to the reed switch, exceeding the switches switching capacity.
Floats specific gravity does not match the liquid that is being measured
Wire color does not match level switch. When connected to one switch, attempt to activate/deactivate all switches to determine which switch is connected to what wire color.