Like RFREY1 said, the governor will attempt to increase the pressure when you run out of/low on water. Once the sensors realize that the pressure is not increasing above the required PSI, it should drop to idle.
No or Low Supply Water
There are situations during pump operations when there may be no or low supply water. This can be due to an empty water tank, a problem on the intake line, or when switching the water supply source.
In pressure mode the INControl will increase the engine RPM and attempt to maintain the selected pressure setting. If the discharge pressure drops below 45 PSI but stays above 15 PSI the INControl will go into a low water cycle. It will set the engine to 1100 RPM, if the pressure does not rise above 45 PSI in 7 seconds the INControl will set the engine at idle RPM. The INControl will repeat the low water cycle as long as the discharge pressure is between 15 and 45 PSI.
If during the prime cycle the discharge pressure drops below 15 PSI the engine will be set at idle RPM. When the discharge pressure rises above 45 PSI the INControl will resume normal operation.