Today I had success, corrected po's mechanics bad wiring, they had a problem with HW heater wires being disturbed when gkids piled in closet and broke out the floor.
Turned out only the gas sensor wire was disconnected, but he preceeded to cut the supply line at the WH and at the Main breaker box, then added a wire from the breaker to the water heater, he told previous owners that they would have to use the circuit breaker to turn on and off, not the AS switch in the bathroom. When I checked his wiring I found he had wired the wh through the tiny 6 amp sensor switch at the water heater and bypassed the bathroom. He missed the disconnected wire for the gas igniter circuit. Too bad all romex wires look the same
and he didn't have the knowledge to test continuty of a wire disconnected by a switch.
I'm sure it took me longer to figure out his mistake than he took to repair, also took longer to connect to the stubs he left when he cut the romex from the water heater and the breaker
LY 30 MH 2000