New bradford white h/w tank installed yesterday by plummer. No hot water. Seems to be the circuit breaker for the h/w. circuit will not reset when tripped. How do I replace the circuit breaker? I will shut off main circuit, but does the breaker pop out? Or do I wedge it out

I would imagine your first action would have been to call the plumber back that just installed this thing yesterday, not replacing the breaker yourself.

If you paid to have a brand new unit installed it should work like a brand new unit. Am I off base here?

Do not attemp to replace the breaker. Wait for the plumber to return. Did it work while he was still there, when did it first pop?

If you have to ask, don't do it. 240 volts can kill you.