You can mark the start time using the real time clock TIME[1], TIME[2] and TIME[3]. Then at the end of the run use the stop time to minus the start time. Of course if the process runs for more than 24 hours then you will need the date as well.
Another way is to use a timer with SV = 600, and at the end of the time out, trigger a custom function and increment a variable by 1. This keep track of the time the pump runs (in minutes) and to get the hour, just divide the variable by 60.
