Because they're not externally adjustable, they don't need to be located close to the control panel. Depending on your application, you might want your salvaged pressure switch to operate at pressures that are different to its standard range. That's not hard to do if you have a washing machine pressure switch, as they are quite easy to modify.In standard form, turning the adjustment control typically allows the trip pressure to be set to detect water depths anywhere from 9cm to 20cm. But if you remove the adjustment.
During ‘on’ time of spin direction timer IC2, the output of negative- edge triggerd JK flip-flop at pin 2 goes low to energise relay RL2 and washing machine motor rotates in one direction. During the off time of IC2, the output of N1 goes high again to de-energise relay RL1, which cuts off the mains supply to RL2 and the monitor stop rotating. Floating point trouble may occur at trigger pin 2 of IC1. Resister R8 over comes this problem by holding pin 2 high.