More Details
The pumps will not run all the time, only one pump will run (at a time) when it receives a signal from pressure switch.
The two pumps will NEVER run together. The alternation is between them such that both operates equal number of times, ie. if pump 1 operated first time, then next time pump 2 will operate then third time pump 1 , so on.
Both will be off same time when the whole booster is switched off or when the pressure switch does not send a signal.
Pressure switch is normally opened, so when it closes one pump will run, while if it is opened the pump will stop (if it was operating).
Now please find attached diagram for how i thought it maybe. I used two impulse relays but i am not sure i am right because of two reasons:
1- if PS1 was closed, R will be energized, so first NO contact will close and energize IMP1 to operate Pump1 , same time, NC contact of R will open, so will it energize IMP2 or not?? (AS i know impusle relay is energized due to transition not due to maintained power).
2- Probably i am required to do the circuit with only one impulse relay.
Thank you so much for your interest in my issue, and sory for the long details.