This unit (MP-3A) was designed with an inlet voltage of either 240V or 208V. This system was not designed for operation with a 120V inlet source or source to any components in the still. The 240V or 208V stills feed that same main line voltage of the still to the heating elements, contacts of the solenoid valves, water switch and off switch. The coils of the solenoid valves and the on switch are fed with a low voltage DC source (24 VDC).
I hope this information helps to answer your question about the operation of the Mega-Pure Still. If you need parts or additional information regarding this still, please feel free to contact us. We would be happy to assist you.