Do I have to unplug the Corro-Protec if we turn off the hot water for several months at our cottage?
The Corro-Protec does not require any special maintenance. Leave it connected at all times, and it will work only if necessary. Even if you turn off the hot water tank, if there is still water in the tank, the Corro-Protec will remain functional to prevent corrosion. If you empty the tank, the Corro-Protec will turn off automatically because the water acts as a conductor between the anode and the ground.
An impressed current anode does not function as a heating element. There is no danger in emptying the water from the tank without disconnecting the anode.