Hi Chris,
Obviously this is a new build. I don't see a UD3 model however in H170 series
Am I missing it?
Your CPU fan spins with the system is powered on yes?
5 beeps does sound like CPU problem. Of the few 100 series MB's I have reviewed all support current skylake offerings with initial BIOS release. You should confirm this however.
I'd remove my CPU and inspect the socket for damage. Simply reseating it might help. Yes, its a pain to clean off the thermal paste, but is worth the piece of mind. Always a (small) chance the CPU is faulty. so if you can check this with the help of a friend or shop may also be a good idea.