I hauld Breyers ice cream on a dedicated account , we had special trailers to haul it with 6 inch walls and ceiling and a 100 gallon fuel tank , and they only got shut off for maintenance. They used to spray the trailer with a fire hose to cool it off in the summer , id stay away from ice cream in the summer with a standard reefer trailer. I liked hauling ice cream it was no touch and the receiver unloaded it lickity split not wanting to melt it.
I've learned over the years the r rating in the walls will deteriorate thus making it harder to cool in hot weather. Cooling an empty box to temp is always tougher. I have a 18 Dane with thermoguard walls. Carrier 7500. Empty in 90+ with humidity takes 2 hours to get to -10, 3 hours to -20 but it will do it. Ice cream always run on continuous. In the end, the proper equipment is the best strategy. I went biggest baddest mofo unit out there with the best insulation I could get outside of going specific ice cream trailer which you lose cube space because of thicker walls. Annual pm, condenser cleaning at the beginning of the warm season is a must.
Yes that is normal and takes even longer, if you don't pre cool. And if your unit reached -20 in that amount of time, your unit is running very well. There is ABSOLUTELY nothing wrong with it.
That is an excellent unit. Basically its is the newer version of the SB 330. They stopped making the SB
You really dont need to do that, unless your unit is struggling to get to the temperature, and you are having an alarm for high discharge temperature. Your unit is running like it should.