GT has good incoming AC, but the unit is faulting with a AC Voltage Fault.
The unit requires a operating range from the utility
operating range for the unit,
utility voltage (L1 L2) @ 240V=212-263Vac @208=184-228 Vac
utility voltage (L1 N) @ 240V or 208V=106.1- 131.5 Vac
The unit may have a blown AC fuse. The continuity of the AC can be checked by a qualified person.
If the fuse is good and the AC voltage is in range, call in for RMA. Proof of warranty status required.
1-PH Tech Support : 714-708-4752