I received a Hayward H350 heater (used) and had my pool guy hook it up. The problem is that the control panel does not light up and we cannot turn on the heater. He tells me he tested and there is power going to the inside of the heater (I don't know exactly where he checked). Of note this heater had been hooked up to a 240V source and I have 120V; he switched this at the beginning of the hook up.
I realize there are a lot of variables at play here, but if anybody has any ideas as to where to look I'd appreciate it. If this can be solved without replacing the control unit that would certainly help.