What do the error codes E-1, E-2, and E-3 mean on the Miller XMT 304?

E-1 indicates an overtemperature condition—allow the unit to cool down before continuing. E-2 signals an overcurrent condition—reduce the welding current or check for short circuits. E-3 indicates an input voltage error—verify that the input voltage matches the unit's requirements of 208–230/460V, 3-phase.