In the Programs tab, at the bottom of the screen are options for Repeat XXX. If you set any one of those to "0", it will repeat that until stopped. Most of us use "Repeat Sequence" to run programs via remote.
You may need to be careful, however, in running only one Frequency for many repeats. Some people are rather sensitive to one frequency running a long time without changing to something else. I need to have 3 or 4 frequencies in the rotation to allow it to run for a number of hours.
For more details, please check this link: