Originally Posted by ChuckO
Yes, the BCS can control any voltage supply. The BCS outputs 5v. signals to drive solid state relays which do the actual switching of the high current load. SSR's can be purchased that can control 50-600 volts, so there should be no problem. Look around here for various schematics and you will find examples of systems that use either the BCS or a PID to control the relays.
Not trying to hijack; rather expand upon the OP...
With two 120v elements would you use two SSR's and connect them in parallel to the PID?
EDIT: That is, in a case where I'd be using two 120v elements in the BK. Two to bring to a boil; one to maintain a boil.