I have always wired motors as 220v if I can just to have less wear and tear on the windings less volts more amps more heat faster insulation breakdown on a motor
Valves on the outside you mean the suction and discharge of the compressor correct
Yes you will need to open those valves for a vaccumm test and a nitrogen test if you don't have nitrogen use and inherit gas like argon, I would pressure test both high and low side to 100#psig
Upon blowing the...