I am wondering if any team’s pressure sensors arrived 10 PSI below what they are supposed to be. Our 115 and 110 PSI pressure switches go off at 105 and 100 PSI respectively. I need to know if the sensors were set wrong or the pressure guage is wrong.
I haven’t looked at the switches yet, but did your try swapping
pressure gauges? Also what is the measured output on the compressor regulator - Ours certainly was tripping at 120 and the
secondary was at sixty. Find it hard to believe both swtiches were so far off. I am not sure if the switches are adjustable.
I also noted (much to my chagrin) that there were many leaks the first time I put the system together. Especially at the pressure tanks. Getting the teflon tape right takes a little practice.
Use a spray bottle of soapy watter to test your connections.
You need to calibrate the sensors correctly. At the very tip of the black end (the one away from the threads), there is a little plastic bump. If you have long enough fingernails, you canjust pop the little plastic top off. Otherwise, get some pliers or something, and pop it off. It might feel like you’re gona break it, but you won’t. After that comes off, there is a little screw/bolt thingy that you can turn to adjust the sensor.
Or, you can not bother with all of that, and make a “magic number”, which is basically X amount of cycles that the system waits after the switch is tripped. It layman’s terms, the swtich trips, and then so mnay cycles later, the compressor shuts off. That’s the way I made mine, mostly because i was too lazy to calibrate the switch. 
I actually found out about this when I was calibrating the sensors so the pump would charge itself. They are adjustable. Remove the rubber cap on the bottom with some pliers or a flat head screwdriver and turn the thing in there with an allen wrench or flat head. Thanks for the help. 