A:  The minimum operating PSI is 10 and the maximum operating PSI is 100.

A:  I do not know. I haven't had any pressure problems. I use large oscillator sprinklers with distance max 42 ft. I use it to water with small stake sprinklers. I have about 15 give or take about 2 and the pressure stays the same at each head.

A:  Contact Orbit www.orbitonline.com. "Schedule a Call Back (800) 488-6156 or Text Us (801) 797-2319."

A:  For replacement parts, please contact our Orbit support team by phone at (800) 488-6156 or online at support.orbitonline.com.

A:  yes, You can program 3 schedules (called ZONES A, B, and C). You can assign any or all of the 4 stations (hoses) to open and water according to the scheduled time and duration you set for each zone (schedule).

A:  I was not happy with this Orbit. I returned and bought the Melnor. You can program 4 outlets to water 4 separate zones up to 4 different cycles at different times. You ca program separate days or all days. 

A:  You can find the directions online. there are videos on you tube. You can also print the manual.

A:  For help with setup and programming, please contact our Orbit support team by phone at (800) 488-6156 or online at support.orbitonline.com.

A:  https://manualzz.com/doc/53237123/orbit-56545-4-outlet-integrated-watering-system-installat...

A:  Pull it up online.   First thing to know, when you set the start time it will run one hose after another. You can set for different times by setting zones. So, if you want one hose to run daily, and another to run every other day, you will do that by the zone buttons.  They come up as A, B, C, seen on the face of the display.  You change zones by the arrow button.  First, set time. Put on set clock, push positive or minus signed buttons Then go to start time. That will start a cycle for whichever hoses you want to run one after another.  (Zones are ABC, horizontal on display, hoses, stations, are 1234, vertical on display. ) Set that time.  Then go to how long.  You manually set those individual run times, changing the hose you are using with the station button.  How often will be set by the ABC  How often can either be set individually by day, or intermittently by going down to the INT.  Use the +,- buttons to set if you want it on or off that day.  So you can set it on on Saturday, but off on Sunday.  When done, just put on Auto and sit back and enjoy.   Hope this was not too confusing, but as stated in first sentence, you should be able to find instructions that will be clearer online.