We have a Ruudglas Pacemaker Serial #0278 04649 Model RP 40-2 E.C.O. water heater. It is connected to a timer also. It stopped producing hot water all of a sudden. We have Do-It-Yourself book that's says we need to test it first with a multi meter device, whatever that is. We already checked the circuit breaker, it's not tripped. We are not sure what to do next, other than call a repairman or buy a new unit.