I'm in south florida and I'm thinking about installing a new tankless water heater (Titan SCR-2, Model N-120) The installation requires #6 wire and a double pole 60 amp breaker. I currently have a tank water heater with a double pole 25 amp breaker. I haven't looked at the existing wire, but I'm guessing it isn't #6, so would my approach be to just replace the 25 amp breaker with the 60 amp breaker and then pull the old wire out and run the new wire where the old wire was? Or would it make sense to leave the existing breaker and wire in place in case a future owner ever goes back to a tank water heater. I would appreciate any advice with this, and any other issues you think I might encounter with this installation. Thanks!

I have a switch box (box 1) with a blank on one side and a dimmer switch on the other side. The dimmer switch controls 2 chandelier type lights over a long dining table. The dimmer switch has a red, black, white and ground attached. Also in that same box, are 3 white wire nutted together, 3 black wire nutted together, 1 ground, 1 red capped. Across the kitchen, there is a switch box (box 2) with a double pole switch in one position and a dimmer switch on the other side. The double pole switch also controls the lights over the dining table. The dimmer switch controls recessed lighting in the ceiling. The double pole switch has red, black, white, ground attached. The dimmer switch has 2 black and a ground. Also in that same box, are 3 white wire nutted together, 3 black wire nutted together. We are replacing the dimmer switches with standard switches so that we can use cfl bulbs that are non-dimmable. In box 1 what color wires go to a standard 2 pole switch? We would still like the ability to turn off the lights at the dining table at both boxes. In box 2 does the standard switch still get 2 black wires? Thanks ellie