if there's no need to monitor anything else, you could simply use a delay.
but you still need to recognize the event
if (psi >= Stop )
the above is repeated numerous times. it would make more sense that there is simply one place where that condition is tested and executed. same for
if (psi<=Start)
not clear what the RedEnd input should do. it prevents other actions for 1 minute, but it is not like on on off switch