With increasing flow when the float passes up in front of the switch the switch becomes open. (Break to alarm) Even if the float goes up beyond the level the switch remains open i.e. it latches off. Unless the float comes down and goes below the high level, the switch will not turn on. Thus the switch is Bi-stable with  stable states

The switch operates by sensing the direction of the float travel. For the high limit switch when the float is below the high limit the switch remains on, indicating normal condition

For the low flow switch, similar action happens with the switch remaining off when the float goes