Hello my name is Mike, I will be assisting you with this problem today. Thanks for trusting us to help you with this appliance question.
The temp for the freezer should be around 0 to -10f, if the unit has been running for a while then that is where it should be, if the unit was only installed today then it take around 12 hours for the unit to get down to the set temp.
If you have owned this for more then a day I would keep a eye on things for around 24 hours, if you are still reading 15f by say tomorrow you do indeed have a problem that needs to be addressed.
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