Hello, my name is ***** ***** I am going to assist you with this.
Since your unit is brand new, it is still under warranty, and you are going to be very limited in what you can do without voiding your warranty.
However, by setting a code 15, and now not even starting, this points heavily to a lack of fuel
Make sure your LP tank is full and turned on.
If the unit had run out of LP, or you had changed tanks, there may be air in the line. Make sure all air is purged from the line.
If it still will not start, check to see if you are getting spark to the plug.
Let me know what you find.