just a doubt, a walk in freezer should have at least 4 30 minute defrosts per 24 hr. period and most of the times i see them at 6 hours apart. What if i was to set a 15 minute defrost every 2 hours? .. would that be bad or can it be good ?

Thanks!

Probably not good, too often and possibly insufficient time..

The frequency of defrost cycles is determined by the load and the amount of moisture that the system has to deal with. With a good tight box, moderate load, and few door openings a freezer can get by with 2 or even in some cases one defrost per day.

Most restaurants have too much in/out traffic for that so 4 cycles a day had become the default setting and 30-45 minutes the typical duration.

With the Grasslin clocks you can set different durations for different events. For example, a longer defrost in the afternoon because of in/out traffic during the day and shorter durations during the night or early morning when the door stays shut.

In the Heatcraft Beacon 2 system you can enable Smart Defrost which only uses defrost cycles when they are needed and only as long as needed to clear the coil. The company claims some significant energy savings with this.